SeaBIOS

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3783 discussions

Re: [SeaBIOS] [RFC PATCH v2 5/6] hw/pci: add bus_reserve property to pcie-root-port
by Michael S. Tsirkin 29 Jul '17

29 Jul '17

On Tue, Jul 25, 2017 at 12:41:12AM +0300, Alexander Bezzubikov wrote: > 2017-07-24 23:46 GMT+03:00 Michael S. Tsirkin <mst(a)redhat.com>: > > On Sun, Jul 23, 2017 at 05:13:11PM +0300, Marcel Apfelbaum wrote: > >> On 23/07/2017 15:22, Michael S. Tsirkin wrote: > >> > On Sun, Jul 23, 2017 at 01:15:42AM +0300, Aleksandr Bezzubikov wrote: > >> > > To enable hotplugging of a newly created pcie-pci-bridge, > >> > > we need to tell firmware (SeaBIOS in this case) > >> > > >> > >> Hi Michael, > >> > >> > Presumably, EFI would need to support this too? > >> > > >> > >> Sure, Eduardo added to CC, but he is in PTO now. > >> > >> > > to reserve > >> > > additional buses for pcie-root-port, that allows us to > >> > > hotplug pcie-pci-bridge into this root port. > >> > > The number of buses to reserve is provided to the device via a corresponding > >> > > property, and to the firmware via new PCI capability (next patch). > >> > > The property's default value is 1 as we want to hotplug at least 1 bridge. > >> > > >> > If so you should just teach firmware to allocate one bus # > >> > unconditionally. > >> > > >> > >> That would be a problem for the PCIe machines, since each PCIe > >> devices is plugged in a different bus and we are already > >> limited to 256 PCIe devices. Allocating an extra-bus always > >> would really limit the PCIe devices we can use. > > > > But this is exactly what this patch does as the property is added to all > > buses and default to 1 (1 extra bus). > > > >> > But why would that be so? What's wrong with a device > >> > directly in the root port? > >> > > >> > >> First, plugging a legacy PCI device into a PCIe Root Port > >> looks strange at least, and it can;t be done on real HW anyway. > >> (incompatible slots) > > > > You can still plug in PCIe devices there. > > > >> Second (and more important), if we want 2 or more PCI > >> devices we would loose both IO ports space and bus numbers. > > > > What I am saying is maybe default should not be 1. > > The only sensible variant left is 0. > But as we want pcie-pci-bridge to be used for every legacy PCI device > on q35 machine, every time one hotplugs the bridge into the root port, > he must be sure rp's prop value >0 (for Linux). I'm not sure > that it is a very convenient way to utilize the bridge - always remember > to set property. That's what I'm saying then - if in your opinion default is >0 anyway, tweak firmware to do it by default. > Another way - we can set this to 0 by default, and to 1 for pcie-root-port, > and recommend to use it for hotplugging of the pcie-pci-bridge itself. I wonder about something: imagine hotplugging a hierarchy of bridges below a root port. It seems that nothing prevents guest from finding a free range of buses to cover this hierarchy and setting that as secondary/subordinate bus for this bridge. This does need support on QEMU side to hotplug a hierarchy at once, and might need some fixes in Linux, on the plus side you can defer management decision on how many are needed until you are actually adding something, and you don't need vendor specific patches. > > > >> > > >> > > > >> > > Signed-off-by: Aleksandr Bezzubikov <zuban32s(a)gmail.com> > >> > > --- > >> > > hw/pci-bridge/pcie_root_port.c | 1 + > >> > > include/hw/pci/pcie_port.h | 3 +++ > >> > > 2 files changed, 4 insertions(+) > >> > > > >> > > diff --git a/hw/pci-bridge/pcie_root_port.c b/hw/pci-bridge/pcie_root_port.c > >> > > index 4d588cb..b0e49e1 100644 > >> > > --- a/hw/pci-bridge/pcie_root_port.c > >> > > +++ b/hw/pci-bridge/pcie_root_port.c > >> > > @@ -137,6 +137,7 @@ static void rp_exit(PCIDevice *d) > >> > > static Property rp_props[] = { > >> > > DEFINE_PROP_BIT(COMPAT_PROP_PCP, PCIDevice, cap_present, > >> > > QEMU_PCIE_SLTCAP_PCP_BITNR, true), > >> > > + DEFINE_PROP_UINT8("bus_reserve", PCIEPort, bus_reserve, 1), > >> > > DEFINE_PROP_END_OF_LIST() > >> > > }; > >> > > diff --git a/include/hw/pci/pcie_port.h b/include/hw/pci/pcie_port.h > >> > > index 1333266..1b2dd1f 100644 > >> > > --- a/include/hw/pci/pcie_port.h > >> > > +++ b/include/hw/pci/pcie_port.h > >> > > @@ -34,6 +34,9 @@ struct PCIEPort { > >> > > /* pci express switch port */ > >> > > uint8_t port; > >> > > + > >> > > + /* additional buses to reserve on firmware init */ > >> > > + uint8_t bus_reserve; > >> > > }; > >> > > void pcie_port_init_reg(PCIDevice *d); > >> > > >> > So here is a property and it does not do anything. > >> > It makes it easier to work on series maybe, but review > >> > is harder since we do not see what it does at all. > >> > Please do not split up patches like this - you can maintain > >> > it split up in your branch if you like and merge before sending. > >> > > >> > >> Agreed, Alexandr please merge patches 4-5-6 for your next submission. > >> > >> Thanks, > >> Marcel > >> > >> > >> > > -- > >> > > 2.7.4 > > > > -- > Alexander Bezzubikov

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Re: [SeaBIOS] [Qemu-devel] Commit 77af8a2b95b79699de650965d5228772743efe84 breaks Windows 2000 support
by Paolo Bonzini 28 Jul '17

28 Jul '17

On 25/07/2017 18:23, Paolo Bonzini wrote: > On 25/07/2017 18:14, Laszlo Ersek wrote: >> "No regressions became apparent in tests with a range of Windows >> (XP-10)" >> >> In theory, w2k falls within that range. > > Nope, Windows 2000 is like NT 5.0, XP is like NT 5.1. :( > > One possibility is to fix it in SeaBIOS instead: if you get a 2.0 FADT > and an XSDT and no RSDT, it can build an RSDT and a 1.0 FADT itself, > patching the RSDT to point to it. > > It's a hack, but it's the only place I see to make it "just work". And > it could be extended nicely in the future. > > All QEMU would have to do is to provide an XSDT _instead_ of an RSDT. Completely untested code follows. Machine type compatibility code should not be necessary because new QEMU always starts with a new BIOS. Not sure I'll have much time for this in the next few days, so help is appreciated. Paolo QEMU: diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c index 36a6cc450e..ea750d54d9 100644 --- a/hw/acpi/aml-build.c +++ b/hw/acpi/aml-build.c @@ -1573,33 +1573,6 @@ void acpi_build_tables_cleanup(AcpiBuildTables *tables, bool mfre) g_array_free(tables->vmgenid, mfre); } -/* Build rsdt table */ -void -build_rsdt(GArray *table_data, BIOSLinker *linker, GArray *table_offsets, - const char *oem_id, const char *oem_table_id) -{ - int i; - unsigned rsdt_entries_offset; - AcpiRsdtDescriptorRev1 *rsdt; - const unsigned table_data_len = (sizeof(uint32_t) * table_offsets->len); - const unsigned rsdt_entry_size = sizeof(rsdt->table_offset_entry[0]); - const size_t rsdt_len = sizeof(*rsdt) + table_data_len; - - rsdt = acpi_data_push(table_data, rsdt_len); - rsdt_entries_offset = (char *)rsdt->table_offset_entry - table_data->data; - for (i = 0; i < table_offsets->len; ++i) { - uint32_t ref_tbl_offset = g_array_index(table_offsets, uint32_t, i); - uint32_t rsdt_entry_offset = rsdt_entries_offset + rsdt_entry_size * i; - - /* rsdt->table_offset_entry to be filled by Guest linker */ - bios_linker_loader_add_pointer(linker, - ACPI_BUILD_TABLE_FILE, rsdt_entry_offset, rsdt_entry_size, - ACPI_BUILD_TABLE_FILE, ref_tbl_offset); - } - build_header(linker, table_data, - (void *)rsdt, "RSDT", rsdt_len, 1, oem_id, oem_table_id); -} - /* Build xsdt table */ void build_xsdt(GArray *table_data, BIOSLinker *linker, GArray *table_offsets, diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c index 6b7bade183..ad00f6affd 100644 --- a/hw/i386/acpi-build.c +++ b/hw/i386/acpi-build.c @@ -2557,12 +2557,12 @@ build_amd_iommu(GArray *table_data, BIOSLinker *linker) } static GArray * -build_rsdp(GArray *rsdp_table, BIOSLinker *linker, unsigned rsdt_tbl_offset) +build_rsdp(GArray *rsdp_table, BIOSLinker *linker, unsigned xsdt_tbl_offset) { AcpiRsdpDescriptor *rsdp = acpi_data_push(rsdp_table, sizeof *rsdp); - unsigned rsdt_pa_size = sizeof(rsdp->rsdt_physical_address); - unsigned rsdt_pa_offset = - (char *)&rsdp->rsdt_physical_address - rsdp_table->data; + unsigned xsdt_pa_size = sizeof(rsdp->xsdt_physical_address); + unsigned xsdt_pa_offset = + (char *)&rsdp->xsdt_physical_address - rsdp_table->data; bios_linker_loader_alloc(linker, ACPI_BUILD_RSDP_FILE, rsdp_table, 16, true /* fseg memory */); @@ -2571,8 +2571,8 @@ build_rsdp(GArray *rsdp_table, BIOSLinker *linker, unsigned rsdt_tbl_offset) memcpy(rsdp->oem_id, ACPI_BUILD_APPNAME6, 6); /* Address to be filled by Guest linker */ bios_linker_loader_add_pointer(linker, - ACPI_BUILD_RSDP_FILE, rsdt_pa_offset, rsdt_pa_size, - ACPI_BUILD_TABLE_FILE, rsdt_tbl_offset); + ACPI_BUILD_RSDP_FILE, xsdt_pa_offset, xsdt_pa_size, + ACPI_BUILD_TABLE_FILE, xsdt_tbl_offset); /* Checksum to be filled by Guest linker */ bios_linker_loader_add_checksum(linker, ACPI_BUILD_RSDP_FILE, @@ -2621,7 +2621,7 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine) PCMachineState *pcms = PC_MACHINE(machine); PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms); GArray *table_offsets; - unsigned facs, dsdt, rsdt, fadt; + unsigned facs, dsdt, xsdt, fadt; AcpiPmInfo pm; AcpiMiscInfo misc; AcpiMcfgInfo mcfg; @@ -2730,12 +2730,12 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine) } /* RSDT is pointed to by RSDP */ - rsdt = tables_blob->len; - build_rsdt(tables_blob, tables->linker, table_offsets, + xsdt = tables_blob->len; + build_xsdt(tables_blob, tables->linker, table_offsets, slic_oem.id, slic_oem.table_id); /* RSDP is in FSEG memory, so allocate it separately */ - build_rsdp(tables->rsdp, tables->linker, rsdt); + build_rsdp(tables->rsdp, tables->linker, xsdt); /* We'll expose it all to Guest so we want to reduce * chance of size changes. SeaBIOS: >From 73b0facdb7349f5dbf24dc675647b68eeeec0ff4 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini <pbonzini(a)redhat.com> Date: Tue, 25 Jul 2017 18:50:19 +0200 Subject: [PATCH 1/2] seabios: build RSDT from XSDT Old operating systems would like to have a v1 FADT, but new operating systems would like to have v3. Since old operating systems do not know about XSDTs, the solution is to point the RSDT to a v1 FADT and the XSDT to a v3 FADT. But, OVMF is not able to do that and barfs when it sees the second FADT---plus really it's only BIOS operating systems such as win2k that complain. So instead: 1) make QEMU provide an XSDT only; 2) build the RSDT and v1 FADT in SeaBIOS. This patch makes SeaBIOS build an RSDT out of an existing XSDT. Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> --- src/fw/paravirt.c | 45 ++++++++++++++++++++++++++++++++++++++++++++- src/std/acpi.h | 11 +++++++++++ 2 files changed, 55 insertions(+), 1 deletion(-) diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c index 5b23d78..19a4abe 100644 --- a/src/fw/paravirt.c +++ b/src/fw/paravirt.c @@ -25,6 +25,7 @@ #include "x86.h" // cpuid #include "xen.h" // xen_biostable_setup #include "stacks.h" // yield +#include "std/acpi.h" // Amount of continuous ram under 4Gig u32 RamSize; @@ -147,6 +148,46 @@ static void msr_feature_control_setup(void) wrmsr_smp(MSR_IA32_FEATURE_CONTROL, feature_control_bits); } +static void +build_compatibility_rsdt(void) +{ + if (RsdpAddr->rsdt_physical_address) + return; + + u64 xsdt_addr = RsdpAddr->xsdt_physical_address; + if (xsdt_addr & ~0xffffffffULL) + return; + + struct xsdt_descriptor_rev1 *xsdt = (void*)(u32)xsdt_addr; + void *end = (void*)xsdt + xsdt->length; + struct rsdt_descriptor_rev1 *rsdt; + int rsdt_size = offsetof(struct rsdt_descriptor_rev1, table_offset_entry[0]); + int i; + for (i=0; (void*)&xsdt->table_offset_entry[i] < end; i++) { + u64 tbl_addr = xsdt->table_offset_entry[i]; + if (!tbl_addr || (tbl_addr & ~0xffffffffULL)) + continue; + rsdt_size += 4; + } + + rsdt = malloc_high(rsdt_size); + RsdpAddr->rsdt_physical_address = (u32)rsdt; + + memcpy(rsdt, xsdt, sizeof(struct acpi_table_header)); + rsdt->signature = RSDT_SIGNATURE; + rsdt->length = rsdt_size; + rsdt->revision = 1; + int j; + for (i=j=0; (void*)&xsdt->table_offset_entry[i] < end; i++) { + u64 tbl_addr = xsdt->table_offset_entry[i]; + if (!tbl_addr || (tbl_addr & ~0xffffffffULL)) + continue; + rsdt->table_offset_entry[j++] = (u32)tbl_addr; + } + + rsdt->checksum -= checksum(rsdt, rsdt_size); +} + void qemu_platform_setup(void) { @@ -186,8 +227,10 @@ qemu_platform_setup(void) RsdpAddr = find_acpi_rsdp(); - if (RsdpAddr) + if (RsdpAddr) { + build_compatibility_rsdt(); return; + } /* If present, loader should have installed an RSDP. * Not installed? We might still be able to continue diff --git a/src/std/acpi.h b/src/std/acpi.h index c2ea707..caf5e7e 100644 --- a/src/std/acpi.h +++ b/src/std/acpi.h @@ -133,6 +133,17 @@ struct rsdt_descriptor_rev1 } PACKED; /* + * ACPI 2.0 Root System Description Table (RSDT) + */ +#define XSDT_SIGNATURE 0x54445358 // RSDT +struct xsdt_descriptor_rev1 +{ + ACPI_TABLE_HEADER_DEF /* ACPI common table header */ + u64 table_offset_entry[0]; /* Array of pointers to other */ + /* ACPI tables */ +} PACKED; + +/* * ACPI 1.0 Firmware ACPI Control Structure (FACS) */ #define FACS_SIGNATURE 0x53434146 // FACS -- 2.13.3 >From 46c7a296d27bd487cfd89a40973b1e61426dfbd0 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini <pbonzini(a)redhat.com> Date: Tue, 25 Jul 2017 18:59:20 +0200 Subject: [PATCH 2/2] seabios: create v1 FADT in compatibility RSDT This patch presents a v1 FADT inside the compatibility RSDT, so that old operating systems are not broken. Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> --- src/fw/paravirt.c | 18 +++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c index 19a4abe..a9b9e80 100644 --- a/src/fw/paravirt.c +++ b/src/fw/paravirt.c @@ -148,6 +148,18 @@ static void msr_feature_control_setup(void) wrmsr_smp(MSR_IA32_FEATURE_CONTROL, feature_control_bits); } +static void* +build_rev1_fadt(struct fadt_descriptor_rev1 *fadt_v3) +{ + struct fadt_descriptor_rev1 *fadt_v1 = malloc_high(sizeof *fadt_v1); + + memcpy(fadt_v1, fadt_v3, sizeof *fadt_v1); + fadt_v1->length = sizeof *fadt_v1; + fadt_v1->revision = 1; + fadt_v1->checksum -= checksum(fadt_v1, fadt_v1->length); + return fadt_v1; +} + static void build_compatibility_rsdt(void) { @@ -182,6 +194,12 @@ build_compatibility_rsdt(void) u64 tbl_addr = xsdt->table_offset_entry[i]; if (!tbl_addr || (tbl_addr & ~0xffffffffULL)) continue; + struct acpi_table_header *tbl = (void*)(u32)tbl_addr; + /* The RSDT should only have an ACPI 1.0 FADT according to + * the spec. + */ + if (tbl->signature == FACP_SIGNATURE && tbl->revision > 1) + tbl_addr = (u32)build_rev1_fadt((void *)tbl); rsdt->table_offset_entry[j++] = (u32)tbl_addr; } -- 2.13.3

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[RFC PATCH v2 0/4] Allow RedHat PCI bridges reserve more buses than necessary during init
by Aleksandr Bezzubikov 28 Jul '17

28 Jul '17

Now PCI bridges get a bus range number on a system init, basing on currently plugged devices. That's why when one wants to hotplug another bridge, it needs his child bus, which the parent is unable to provide (speaking about virtual device). The suggested workaround is to have vendor-specific capability in Red Hat PCI bridges that contains number of additional bus to reserve on BIOS PCI init. So this capability is intented only for pure QEMU->SeaBIOS usage. Considering all aforesaid, this series is directly connected with QEMU RFC series (v2) "Generic PCIE-PCI Bridge". Although the new PCI capability is supposed to contain various limits along with bus number to reserve, now only its full layout is proposed, but only bus_reserve field is used in QEMU and BIOS. Limits usage is still a subject for implementation as now the main goal of this series to provide necessary support from the firmware side to PCIE-PCI bridge hotplug. Changes v1->v2: 1. New #define for Red Hat vendor added (addresses Konrad's comment). 2. Refactored pci_find_capability function (addresses Marcel's comment). 3. Capability reworked: - data type added; - reserve space in a structure for IO, memory and prefetchable memory limits. Aleksandr Bezzubikov (4): pci: refactor pci_find_capapibilty to get bdf as the first argument instead of the whole pci_device pci: add RedHat vendor ID pci: add QEMU-specific PCI capability structure pci: enable RedHat PCI bridges to reserve additional buses on PCI init src/fw/pciinit.c | 18 ++++++++++++++---- src/hw/pci_cap.h | 23 +++++++++++++++++++++++ src/hw/pci_ids.h | 2 ++ src/hw/pcidevice.c | 12 ++++++------ src/hw/pcidevice.h | 2 +- src/hw/virtio-pci.c | 4 ++-- 6 files changed, 48 insertions(+), 13 deletions(-) create mode 100644 src/hw/pci_cap.h -- 2.7.4

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Re: [SeaBIOS] Commit 77af8a2b95b79699de650965d5228772743efe84 breaks Windows 2000 support
by Programmingkid 27 Jul '17

27 Jul '17

I just realized what we need in order to test QEMU better. We need a list of people who are willing to support a certain operating system. The list would probably be located here: http://wiki.qemu.org/Testing/Windows It would look like this: Operating system Tester Windows 3.1 <email address of a tester>, <email address of another tester>, ... Windows NT 3.1 <email address of a tester>, <email address of another tester>, ... Windows NT 3.5 <email address of a tester>, <email address of another tester>, ... Windows 95 <email address of a tester>, <email address of another tester>, ... Windows NT 4.0 <email address of a tester>, <email address of another tester>, ... Windows 98 <email address of a tester>, <email address of another tester>, ... Windows ME <email address of a tester>, <email address of another tester>, ... Windows 2000 <email address of a tester>, <email address of another tester>, ... Windows XP <email address of a tester>, <email address of another tester>, ... Windows Vista <email address of a tester>, <email address of another tester>, ... Windows 7 <email address of a tester>, <email address of another tester>, ... Windows 8 <email address of a tester>, <email address of another tester>, ... Windows 10 <email address of a tester>, <email address of another tester>, ... ReactOS <email address of a tester>, <email address of another tester>, ... If someone has a patch that makes a change to the qemu-system-i386 emulator, the patch maker can consult the list of people who might be willing to help test the patch. There are many people who work on QEMU with certain versions of Windows at their disposal. With this knowledge compatibility testing can become more thorough. Thoughts? Ideas?

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Re: [SeaBIOS] [RFC PATCH v2 4/6] hw/pci: introduce bridge-only vendor-specific capability to provide some hints to firmware
by Laszlo Ersek 27 Jul '17

27 Jul '17

On 07/26/17 23:54, Alexander Bezzubikov wrote: > 2017-07-26 22:43 GMT+03:00 Michael S. Tsirkin <mst(a)redhat.com>: >> On Sun, Jul 23, 2017 at 01:15:41AM +0300, Aleksandr Bezzubikov wrote: >>> + PCIBridgeQemuCap cap; >> >> This leaks info to guest. You want to init all fields here: >> >> cap = { >> .len = .... >> }; > > I surely can do this for len field, but as Laszlo proposed > we can use mutually exclusive fields, > e.g. pref_32 and pref_64, the only way I have left > is to use ternary operator (if we surely need this > big initializer). Keeping some if's would look better, > I think. I think it's fine to use "if"s in order to set up the structure partially / gradually, but then please clear the structure up-front: PCIBridgeQemuCap cap = { 0 }; (In general "{ 0 }" is the best initializer ever, because it can zero-init a variable of *any* type at all. Gcc might complain about the inexact depth of {} nesting of course, but it's nonetheless valid C.) Or else add a memset-to-zero. Or else, do just PCIBridgeQemuCap cap = { .len = ... }; which will zero-fill every other field. ("[...] all subobjects that are not initialized explicitly shall be initialized implicitly the same as objects that have static storage duration"). Thanks Laszlo

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[RFC PATCH v2 0/6] Generic PCIE-PCI Bridge
by Aleksandr Bezzubikov 27 Jul '17

27 Jul '17

This series introduces a new device - generic PCI Express to PCI bridge, and also makes all necessary changes to enable hotplug of the bridge itself and any device into the bridge. Obvious reasons to remain RFC: 1. The new PCI capability: layout, creation interface. 2. Windows SHPC issue - devices hotplugging into the bridge doens't work on Windows 7 (unlike Windows 10), whereas an old pci-bridge usage is fine. 3. Hot-unplug not completely tested. Changes v1->v2: 1. Enable SHPC for the bridge. 2. Enable SHPC support for the Q35 machine (ACPI stuff). 3. Introduce PCI capability to help firmware on the system init. This allows the bridge to be hotpluggable. Now it's supported only for pcie-root-port. Now it's supposed to used with SeaBIOS only, look at the SeaBIOS corresponding series "". Aleksandr Bezzubikov (6): hw/pci: introduce pcie-pci-bridge device hw/i386: allow SHPC for Q35 machine hw/pci: enable SHPC for PCIE-PCI bridge hw/pci: introduce bridge-only vendor-specific capability to provide some hints to firmware hw/pci: add bus_reserve property to pcie-root-port hw/pci: add hint capabilty for additional bus reservation to pcie-root-port hw/i386/acpi-build.c | 2 +- hw/pci-bridge/Makefile.objs | 2 +- hw/pci-bridge/pcie_pci_bridge.c | 212 ++++++++++++++++++++++++++++++++++++++++ hw/pci-bridge/pcie_root_port.c | 6 ++ hw/pci/pci_bridge.c | 27 +++++ include/hw/pci/pci.h | 1 + include/hw/pci/pci_bridge.h | 18 ++++ include/hw/pci/pcie_port.h | 3 + 8 files changed, 269 insertions(+), 2 deletions(-) create mode 100644 hw/pci-bridge/pcie_pci_bridge.c -- 2.7.4

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Re: [SeaBIOS] [Qemu-devel] Commit 77af8a2b95b79699de650965d5228772743efe84 breaks Windows 2000 support
by Paolo Bonzini 26 Jul '17

26 Jul '17

On 25/07/2017 23:25, Phil Dennis-Jordan wrote: > Thanks for this, Paolo. Very interesting idea. > > I couldn't get things working initially, but with a few fixups on the > SeaBIOS side I can boot both legacy and modern OSes. See comments > inline below for details on changes required. > > Successfully booted (only a brief test): > - Windows 2000 > - Windows XP (32 bit) > - Windows 7 (32 bit) > - Windows 10 (64 bit, SeaBIOS) > - Windows 10 (64 bit, OVMF) > - macOS 10.12 (patched OVMF) Thanks Phil! You unwittingly tested the compatibility path on all these OSes, since my QEMU patch forgot to setup rsdp->length, rsdp->revision and the extended checksum. However, I've now tested Windows XP, Linux w/SeaBIOS, Linux w/patched SeaBIOS and Linux w/OVMF. I've now found out that edk2 contains similar logic. It uses a PCD (a compile-time flag essentially) to choose between ACPI >= 2.0 tables or ACPI 1.0-compatible tables. In the latter case, edk2 takes care of producing a v1 FADT if needed (similar to this patch) and linking the RSDT to it; otherwise it keeps whatever FADT was provided by platform code and produces an XSDT. So I'm promoting the SeaBIOS code from "hack" to "right thing to do". Though then I cannot brag about Kevin's nice words, too bad. :) Paolo > On Tue, Jul 25, 2017 at 7:10 PM, Paolo Bonzini <pbonzini(a)redhat.com> wrote: >> On 25/07/2017 18:23, Paolo Bonzini wrote: >>> On 25/07/2017 18:14, Laszlo Ersek wrote: >>>> "No regressions became apparent in tests with a range of Windows >>>> (XP-10)" >>>> >>>> In theory, w2k falls within that range. >>> >>> Nope, Windows 2000 is like NT 5.0, XP is like NT 5.1. :( >>> >>> One possibility is to fix it in SeaBIOS instead: if you get a 2.0 FADT >>> and an XSDT and no RSDT, it can build an RSDT and a 1.0 FADT itself, >>> patching the RSDT to point to it. >>> >>> It's a hack, but it's the only place I see to make it "just work". And >>> it could be extended nicely in the future. >>> >>> All QEMU would have to do is to provide an XSDT _instead_ of an RSDT. >> >> Completely untested code follows. Machine type compatibility code >> should not be necessary because new QEMU always starts with a new BIOS. >> >> Not sure I'll have much time for this in the next few days, so help >> is appreciated. >> >> Paolo >> >> QEMU: >> >> diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c >> index 36a6cc450e..ea750d54d9 100644 >> --- a/hw/acpi/aml-build.c >> +++ b/hw/acpi/aml-build.c >> @@ -1573,33 +1573,6 @@ void acpi_build_tables_cleanup(AcpiBuildTables *tables, bool mfre) >> g_array_free(tables->vmgenid, mfre); >> } >> >> -/* Build rsdt table */ >> -void >> -build_rsdt(GArray *table_data, BIOSLinker *linker, GArray *table_offsets, >> - const char *oem_id, const char *oem_table_id) >> -{ >> - int i; >> - unsigned rsdt_entries_offset; >> - AcpiRsdtDescriptorRev1 *rsdt; >> - const unsigned table_data_len = (sizeof(uint32_t) * table_offsets->len); >> - const unsigned rsdt_entry_size = sizeof(rsdt->table_offset_entry[0]); >> - const size_t rsdt_len = sizeof(*rsdt) + table_data_len; >> - >> - rsdt = acpi_data_push(table_data, rsdt_len); >> - rsdt_entries_offset = (char *)rsdt->table_offset_entry - table_data->data; >> - for (i = 0; i < table_offsets->len; ++i) { >> - uint32_t ref_tbl_offset = g_array_index(table_offsets, uint32_t, i); >> - uint32_t rsdt_entry_offset = rsdt_entries_offset + rsdt_entry_size * i; >> - >> - /* rsdt->table_offset_entry to be filled by Guest linker */ >> - bios_linker_loader_add_pointer(linker, >> - ACPI_BUILD_TABLE_FILE, rsdt_entry_offset, rsdt_entry_size, >> - ACPI_BUILD_TABLE_FILE, ref_tbl_offset); >> - } >> - build_header(linker, table_data, >> - (void *)rsdt, "RSDT", rsdt_len, 1, oem_id, oem_table_id); >> -} >> - >> /* Build xsdt table */ >> void >> build_xsdt(GArray *table_data, BIOSLinker *linker, GArray *table_offsets, >> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c >> index 6b7bade183..ad00f6affd 100644 >> --- a/hw/i386/acpi-build.c >> +++ b/hw/i386/acpi-build.c >> @@ -2557,12 +2557,12 @@ build_amd_iommu(GArray *table_data, BIOSLinker *linker) >> } >> >> static GArray * >> -build_rsdp(GArray *rsdp_table, BIOSLinker *linker, unsigned rsdt_tbl_offset) >> +build_rsdp(GArray *rsdp_table, BIOSLinker *linker, unsigned xsdt_tbl_offset) >> { >> AcpiRsdpDescriptor *rsdp = acpi_data_push(rsdp_table, sizeof *rsdp); >> - unsigned rsdt_pa_size = sizeof(rsdp->rsdt_physical_address); >> - unsigned rsdt_pa_offset = >> - (char *)&rsdp->rsdt_physical_address - rsdp_table->data; >> + unsigned xsdt_pa_size = sizeof(rsdp->xsdt_physical_address); >> + unsigned xsdt_pa_offset = >> + (char *)&rsdp->xsdt_physical_address - rsdp_table->data; >> >> bios_linker_loader_alloc(linker, ACPI_BUILD_RSDP_FILE, rsdp_table, 16, >> true /* fseg memory */); >> @@ -2571,8 +2571,8 @@ build_rsdp(GArray *rsdp_table, BIOSLinker *linker, unsigned rsdt_tbl_offset) >> memcpy(rsdp->oem_id, ACPI_BUILD_APPNAME6, 6); >> /* Address to be filled by Guest linker */ >> bios_linker_loader_add_pointer(linker, >> - ACPI_BUILD_RSDP_FILE, rsdt_pa_offset, rsdt_pa_size, >> - ACPI_BUILD_TABLE_FILE, rsdt_tbl_offset); >> + ACPI_BUILD_RSDP_FILE, xsdt_pa_offset, xsdt_pa_size, >> + ACPI_BUILD_TABLE_FILE, xsdt_tbl_offset); >> >> /* Checksum to be filled by Guest linker */ >> bios_linker_loader_add_checksum(linker, ACPI_BUILD_RSDP_FILE, >> @@ -2621,7 +2621,7 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine) >> PCMachineState *pcms = PC_MACHINE(machine); >> PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms); >> GArray *table_offsets; >> - unsigned facs, dsdt, rsdt, fadt; >> + unsigned facs, dsdt, xsdt, fadt; >> AcpiPmInfo pm; >> AcpiMiscInfo misc; >> AcpiMcfgInfo mcfg; >> @@ -2730,12 +2730,12 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine) >> } >> >> /* RSDT is pointed to by RSDP */ >> - rsdt = tables_blob->len; >> - build_rsdt(tables_blob, tables->linker, table_offsets, >> + xsdt = tables_blob->len; >> + build_xsdt(tables_blob, tables->linker, table_offsets, >> slic_oem.id, slic_oem.table_id); >> >> /* RSDP is in FSEG memory, so allocate it separately */ >> - build_rsdp(tables->rsdp, tables->linker, rsdt); >> + build_rsdp(tables->rsdp, tables->linker, xsdt); >> >> /* We'll expose it all to Guest so we want to reduce >> * chance of size changes. >> >> >> SeaBIOS: >> >> From 73b0facdb7349f5dbf24dc675647b68eeeec0ff4 Mon Sep 17 00:00:00 2001 >> From: Paolo Bonzini <pbonzini(a)redhat.com> >> Date: Tue, 25 Jul 2017 18:50:19 +0200 >> Subject: [PATCH 1/2] seabios: build RSDT from XSDT >> >> Old operating systems would like to have a v1 FADT, but new >> operating systems would like to have v3. >> >> Since old operating systems do not know about XSDTs, the >> solution is to point the RSDT to a v1 FADT and the XSDT to a >> v3 FADT. >> >> But, OVMF is not able to do that and barfs when it sees the >> second FADT---plus really it's only BIOS operating systems >> such as win2k that complain. So instead: 1) make QEMU provide >> an XSDT only; 2) build the RSDT and v1 FADT in SeaBIOS. >> >> This patch makes SeaBIOS build an RSDT out of an existing XSDT. >> >> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> >> --- >> src/fw/paravirt.c | 45 ++++++++++++++++++++++++++++++++++++++++++++- >> src/std/acpi.h | 11 +++++++++++ >> 2 files changed, 55 insertions(+), 1 deletion(-) >> >> diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c >> index 5b23d78..19a4abe 100644 >> --- a/src/fw/paravirt.c >> +++ b/src/fw/paravirt.c >> @@ -25,6 +25,7 @@ >> #include "x86.h" // cpuid >> #include "xen.h" // xen_biostable_setup >> #include "stacks.h" // yield >> +#include "std/acpi.h" >> >> // Amount of continuous ram under 4Gig >> u32 RamSize; >> @@ -147,6 +148,46 @@ static void msr_feature_control_setup(void) >> wrmsr_smp(MSR_IA32_FEATURE_CONTROL, feature_control_bits); >> } >> >> +static void >> +build_compatibility_rsdt(void) >> +{ >> + if (RsdpAddr->rsdt_physical_address) >> + return; >> + >> + u64 xsdt_addr = RsdpAddr->xsdt_physical_address; >> + if (xsdt_addr & ~0xffffffffULL) >> + return; >> + >> + struct xsdt_descriptor_rev1 *xsdt = (void*)(u32)xsdt_addr; >> + void *end = (void*)xsdt + xsdt->length; >> + struct rsdt_descriptor_rev1 *rsdt; >> + int rsdt_size = offsetof(struct rsdt_descriptor_rev1, table_offset_entry[0]); >> + int i; >> + for (i=0; (void*)&xsdt->table_offset_entry[i] < end; i++) { >> + u64 tbl_addr = xsdt->table_offset_entry[i]; >> + if (!tbl_addr || (tbl_addr & ~0xffffffffULL)) >> + continue; >> + rsdt_size += 4; >> + } >> + >> + rsdt = malloc_high(rsdt_size); >> + RsdpAddr->rsdt_physical_address = (u32)rsdt; > > Modifying the RSDP like this invalidates both its checksums, so they > need to be adjusted. Something like this: > > RsdpAddr->checksum -= checksum(RsdpAddr, offsetof(struct > rsdp_descriptor, length)); > RsdpAddr->extended_checksum -= checksum(RsdpAddr, sizeof(struct > rsdp_descriptor)); > >> + >> + memcpy(rsdt, xsdt, sizeof(struct acpi_table_header)); >> + rsdt->signature = RSDT_SIGNATURE; >> + rsdt->length = rsdt_size; >> + rsdt->revision = 1; >> + int j; >> + for (i=j=0; (void*)&xsdt->table_offset_entry[i] < end; i++) { >> + u64 tbl_addr = xsdt->table_offset_entry[i]; >> + if (!tbl_addr || (tbl_addr & ~0xffffffffULL)) >> + continue; >> + rsdt->table_offset_entry[j++] = (u32)tbl_addr; >> + } >> + >> + rsdt->checksum -= checksum(rsdt, rsdt_size); >> +} >> + >> void >> qemu_platform_setup(void) >> { >> @@ -186,8 +227,10 @@ qemu_platform_setup(void) >> >> RsdpAddr = find_acpi_rsdp(); >> >> - if (RsdpAddr) >> + if (RsdpAddr) { >> + build_compatibility_rsdt(); >> return; >> + } >> >> /* If present, loader should have installed an RSDP. >> * Not installed? We might still be able to continue >> diff --git a/src/std/acpi.h b/src/std/acpi.h >> index c2ea707..caf5e7e 100644 >> --- a/src/std/acpi.h >> +++ b/src/std/acpi.h >> @@ -133,6 +133,17 @@ struct rsdt_descriptor_rev1 >> } PACKED; >> >> /* >> + * ACPI 2.0 Root System Description Table (RSDT) >> + */ > > Comment should be "ACPI 2.0 Extended System Description Table (XSDT)" > >> +#define XSDT_SIGNATURE 0x54445358 // RSDT > > The signature is "XSDT", that works out to 0x58445358 > >> +struct xsdt_descriptor_rev1 >> +{ >> + ACPI_TABLE_HEADER_DEF /* ACPI common table header */ >> + u64 table_offset_entry[0]; /* Array of pointers to other */ >> + /* ACPI tables */ >> +} PACKED; >> + >> +/* >> * ACPI 1.0 Firmware ACPI Control Structure (FACS) >> */ >> #define FACS_SIGNATURE 0x53434146 // FACS >> -- >> 2.13.3 >> >> >> From 46c7a296d27bd487cfd89a40973b1e61426dfbd0 Mon Sep 17 00:00:00 2001 >> From: Paolo Bonzini <pbonzini(a)redhat.com> >> Date: Tue, 25 Jul 2017 18:59:20 +0200 >> Subject: [PATCH 2/2] seabios: create v1 FADT in compatibility RSDT >> >> This patch presents a v1 FADT inside the compatibility RSDT, so >> that old operating systems are not broken. >> >> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> >> --- >> src/fw/paravirt.c | 18 +++++++++++++++ >> 1 file changed, 18 insertions(+) >> >> diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c >> index 19a4abe..a9b9e80 100644 >> --- a/src/fw/paravirt.c >> +++ b/src/fw/paravirt.c >> @@ -148,6 +148,18 @@ static void msr_feature_control_setup(void) >> wrmsr_smp(MSR_IA32_FEATURE_CONTROL, feature_control_bits); >> } >> >> +static void* >> +build_rev1_fadt(struct fadt_descriptor_rev1 *fadt_v3) >> +{ >> + struct fadt_descriptor_rev1 *fadt_v1 = malloc_high(sizeof *fadt_v1); >> + >> + memcpy(fadt_v1, fadt_v3, sizeof *fadt_v1); >> + fadt_v1->length = sizeof *fadt_v1; >> + fadt_v1->revision = 1; > > We should mask out the flags bits that are reserved in ACPI 1.0 as > they refer to fields not present in this revision's FADT. e.g. > > // upper 23 bits reserved in rev1 FADT > fadt_v1->flags &= 0x1ff; > > >> + fadt_v1->checksum -= checksum(fadt_v1, fadt_v1->length); >> + return fadt_v1; >> +} >> + >> static void >> build_compatibility_rsdt(void) >> { >> @@ -182,6 +194,12 @@ build_compatibility_rsdt(void) >> u64 tbl_addr = xsdt->table_offset_entry[i]; >> if (!tbl_addr || (tbl_addr & ~0xffffffffULL)) >> continue; >> + struct acpi_table_header *tbl = (void*)(u32)tbl_addr; >> + /* The RSDT should only have an ACPI 1.0 FADT according to >> + * the spec. >> + */ >> + if (tbl->signature == FACP_SIGNATURE && tbl->revision > 1) >> + tbl_addr = (u32)build_rev1_fadt((void *)tbl); >> rsdt->table_offset_entry[j++] = (u32)tbl_addr; >> } >> >> -- >> 2.13.3 >> >> > > With these changes: > > Reviewed-by: Phil Dennis-Jordan <phil(a)philjordan.eu> >

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Re: [SeaBIOS] [RFC PATCH v2 5/6] hw/pci: add bus_reserve property to pcie-root-port
by Marcel Apfelbaum 26 Jul '17

26 Jul '17

On 25/07/2017 20:11, Alexander Bezzubikov wrote: > > вт, 25 июля 2017 г. в 19:10, Marcel Apfelbaum <marcel(a)redhat.com > <mailto:marcel@redhat.com>>: > > On 25/07/2017 17:09, Alexander Bezzubikov wrote: > > 2017-07-25 16:53 GMT+03:00 Michael S. Tsirkin <mst(a)redhat.com > <mailto:mst@redhat.com>>: > >> On Tue, Jul 25, 2017 at 04:50:49PM +0300, Alexander Bezzubikov > wrote: > >>> 2017-07-25 16:43 GMT+03:00 Michael S. Tsirkin <mst(a)redhat.com > <mailto:mst@redhat.com>>: > >>>> On Sun, Jul 23, 2017 at 05:13:11PM +0300, Marcel Apfelbaum wrote: > >>>>> On 23/07/2017 15:22, Michael S. Tsirkin wrote: > >>>>>> On Sun, Jul 23, 2017 at 01:15:42AM +0300, Aleksandr > Bezzubikov wrote: > >>>>>>> To enable hotplugging of a newly created pcie-pci-bridge, > >>>>>>> we need to tell firmware (SeaBIOS in this case) > >>>>>> > >>>>> > >>>>> Hi Michael, > >>>>> > >>>>>> Presumably, EFI would need to support this too? > >>>>>> > >>>>> > >>>>> Sure, Eduardo added to CC, but he is in PTO now. > >>>>> > >>>>>>> to reserve > >>>>>>> additional buses for pcie-root-port, that allows us to > >>>>>>> hotplug pcie-pci-bridge into this root port. > >>>>>>> The number of buses to reserve is provided to the device > via a corresponding > >>>>>>> property, and to the firmware via new PCI capability (next > patch). > >>>>>>> The property's default value is 1 as we want to hotplug at > least 1 bridge. > >>>>>> > >>>>>> If so you should just teach firmware to allocate one bus # > >>>>>> unconditionally. > >>>>>> > >>>>> > >>>>> That would be a problem for the PCIe machines, since each PCIe > >>>>> devices is plugged in a different bus and we are already > >>>>> limited to 256 PCIe devices. Allocating an extra-bus always > >>>>> would really limit the PCIe devices we can use. > >>>> > >>>> One of the declared advantages of PCIe is easy support for > multiple roots. > >>>> We really should look at that IMHO so we do not need to pile > up hacks. > >>>> > >>>>>> But why would that be so? What's wrong with a device > >>>>>> directly in the root port? > >>>>>> > >>>> > >>>> To clarify, my point is we might be wasting bus numbers by > reservation > >>>> since someone might just want to put pcie devices there. > >>> > >>> I think, changing default value to 0 can help us avoid this, > >>> as no bus reservation by default. If one's surely wants > >>> to hotplug pcie-pci-bridge into this root port in future, > >>> the property gives him such an opportunity. > >>> So, sure need pcie-pci-bridge hotplug -> creating a root port with > >>> bus_reserve > 0. Otherwise (and default) - just as now, no changes > >>> in bus topology. > >> > >> I guess 0 should mean "do not reserve any buses". So I think we > also > >> need a flag to just avoid the capability altogether. Maybe -1? > *That* > >> should be the default. > > > > -1 might be useful if any limit value 0 is legal, but is it? > > If not, we can set every field to 0 and > > this is a sign of avoiding capability since none legal > > values are provided. > > > > As Gerd suggested, this value is not a "delta" but the number > of buses to be reserved behind the bridge. If I got it right, > 0 is not a valid value, since the bridge by definition > has a list one bus behind. > > > Gerd's suggestion was to set min(cap_value, children_found). From such > point of view 0 can be a valid value. > I am lost now :) How can we use the capability to reserve "more" buses since children-found will be always the smaller value? I think you should use max(cap_value, children_found) to ensure you always reserve enough buses for existing children. In this case 0 is actually an invalid value since children_found > 0 for a bridge. Thanks, Marcel > > > Michael, would you be OK with that? > > Thanks, > Marcel > > >> > >>>> > >>>>> First, plugging a legacy PCI device into a PCIe Root Port > >>>>> looks strange at least, and it can;t be done on real HW anyway. > >>>>> (incompatible slots) > >>>>> > >>>>> Second (and more important), if we want 2 or more PCI > >>>>> devices we would loose both IO ports space and bus numbers. > >>>>> > >>>>>> > >>>>>>> > >>>>>>> Signed-off-by: Aleksandr Bezzubikov <zuban32s(a)gmail.com > <mailto:zuban32s@gmail.com>> > >>>>>>> --- > >>>>>>> hw/pci-bridge/pcie_root_port.c | 1 + > >>>>>>> include/hw/pci/pcie_port.h | 3 +++ > >>>>>>> 2 files changed, 4 insertions(+) > >>>>>>> > >>>>>>> diff --git a/hw/pci-bridge/pcie_root_port.c > b/hw/pci-bridge/pcie_root_port.c > >>>>>>> index 4d588cb..b0e49e1 100644 > >>>>>>> --- a/hw/pci-bridge/pcie_root_port.c > >>>>>>> +++ b/hw/pci-bridge/pcie_root_port.c > >>>>>>> @@ -137,6 +137,7 @@ static void rp_exit(PCIDevice *d) > >>>>>>> static Property rp_props[] = { > >>>>>>> DEFINE_PROP_BIT(COMPAT_PROP_PCP, PCIDevice, cap_present, > >>>>>>> QEMU_PCIE_SLTCAP_PCP_BITNR, true), > >>>>>>> + DEFINE_PROP_UINT8("bus_reserve", PCIEPort, > bus_reserve, 1), > >>>>>>> DEFINE_PROP_END_OF_LIST() > >>>>>>> }; > >>>>>>> diff --git a/include/hw/pci/pcie_port.h > b/include/hw/pci/pcie_port.h > >>>>>>> index 1333266..1b2dd1f 100644 > >>>>>>> --- a/include/hw/pci/pcie_port.h > >>>>>>> +++ b/include/hw/pci/pcie_port.h > >>>>>>> @@ -34,6 +34,9 @@ struct PCIEPort { > >>>>>>> /* pci express switch port */ > >>>>>>> uint8_t port; > >>>>>>> + > >>>>>>> + /* additional buses to reserve on firmware init */ > >>>>>>> + uint8_t bus_reserve; > >>>>>>> }; > >>>>>>> void pcie_port_init_reg(PCIDevice *d); > >>>>>> > >>>>>> So here is a property and it does not do anything. > >>>>>> It makes it easier to work on series maybe, but review > >>>>>> is harder since we do not see what it does at all. > >>>>>> Please do not split up patches like this - you can maintain > >>>>>> it split up in your branch if you like and merge before sending. > >>>>>> > >>>>> > >>>>> Agreed, Alexandr please merge patches 4-5-6 for your next > submission. > >>>>> > >>>>> Thanks, > >>>>> Marcel > >>>>> > >>>>> > >>>>>>> -- > >>>>>>> 2.7.4 > >>> > >>> > >>> > >>> -- > >>> Alexander Bezzubikov > > > > > > > > -- > Alexander Bezzubikov

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Re: [SeaBIOS] [RFC PATCH v2 5/6] hw/pci: add bus_reserve property to pcie-root-port
by Michael S. Tsirkin 26 Jul '17

26 Jul '17

On Tue, Jul 25, 2017 at 04:50:49PM +0300, Alexander Bezzubikov wrote: > 2017-07-25 16:43 GMT+03:00 Michael S. Tsirkin <mst(a)redhat.com>: > > On Sun, Jul 23, 2017 at 05:13:11PM +0300, Marcel Apfelbaum wrote: > >> On 23/07/2017 15:22, Michael S. Tsirkin wrote: > >> > On Sun, Jul 23, 2017 at 01:15:42AM +0300, Aleksandr Bezzubikov wrote: > >> > > To enable hotplugging of a newly created pcie-pci-bridge, > >> > > we need to tell firmware (SeaBIOS in this case) > >> > > >> > >> Hi Michael, > >> > >> > Presumably, EFI would need to support this too? > >> > > >> > >> Sure, Eduardo added to CC, but he is in PTO now. > >> > >> > > to reserve > >> > > additional buses for pcie-root-port, that allows us to > >> > > hotplug pcie-pci-bridge into this root port. > >> > > The number of buses to reserve is provided to the device via a corresponding > >> > > property, and to the firmware via new PCI capability (next patch). > >> > > The property's default value is 1 as we want to hotplug at least 1 bridge. > >> > > >> > If so you should just teach firmware to allocate one bus # > >> > unconditionally. > >> > > >> > >> That would be a problem for the PCIe machines, since each PCIe > >> devices is plugged in a different bus and we are already > >> limited to 256 PCIe devices. Allocating an extra-bus always > >> would really limit the PCIe devices we can use. > > > > One of the declared advantages of PCIe is easy support for multiple roots. > > We really should look at that IMHO so we do not need to pile up hacks. > > > >> > But why would that be so? What's wrong with a device > >> > directly in the root port? > >> > > > > > To clarify, my point is we might be wasting bus numbers by reservation > > since someone might just want to put pcie devices there. > > I think, changing default value to 0 can help us avoid this, > as no bus reservation by default. If one's surely wants > to hotplug pcie-pci-bridge into this root port in future, > the property gives him such an opportunity. > So, sure need pcie-pci-bridge hotplug -> creating a root port with > bus_reserve > 0. Otherwise (and default) - just as now, no changes > in bus topology. I guess 0 should mean "do not reserve any buses". So I think we also need a flag to just avoid the capability altogether. Maybe -1? *That* should be the default. > > > >> First, plugging a legacy PCI device into a PCIe Root Port > >> looks strange at least, and it can;t be done on real HW anyway. > >> (incompatible slots) > >> > >> Second (and more important), if we want 2 or more PCI > >> devices we would loose both IO ports space and bus numbers. > >> > >> > > >> > > > >> > > Signed-off-by: Aleksandr Bezzubikov <zuban32s(a)gmail.com> > >> > > --- > >> > > hw/pci-bridge/pcie_root_port.c | 1 + > >> > > include/hw/pci/pcie_port.h | 3 +++ > >> > > 2 files changed, 4 insertions(+) > >> > > > >> > > diff --git a/hw/pci-bridge/pcie_root_port.c b/hw/pci-bridge/pcie_root_port.c > >> > > index 4d588cb..b0e49e1 100644 > >> > > --- a/hw/pci-bridge/pcie_root_port.c > >> > > +++ b/hw/pci-bridge/pcie_root_port.c > >> > > @@ -137,6 +137,7 @@ static void rp_exit(PCIDevice *d) > >> > > static Property rp_props[] = { > >> > > DEFINE_PROP_BIT(COMPAT_PROP_PCP, PCIDevice, cap_present, > >> > > QEMU_PCIE_SLTCAP_PCP_BITNR, true), > >> > > + DEFINE_PROP_UINT8("bus_reserve", PCIEPort, bus_reserve, 1), > >> > > DEFINE_PROP_END_OF_LIST() > >> > > }; > >> > > diff --git a/include/hw/pci/pcie_port.h b/include/hw/pci/pcie_port.h > >> > > index 1333266..1b2dd1f 100644 > >> > > --- a/include/hw/pci/pcie_port.h > >> > > +++ b/include/hw/pci/pcie_port.h > >> > > @@ -34,6 +34,9 @@ struct PCIEPort { > >> > > /* pci express switch port */ > >> > > uint8_t port; > >> > > + > >> > > + /* additional buses to reserve on firmware init */ > >> > > + uint8_t bus_reserve; > >> > > }; > >> > > void pcie_port_init_reg(PCIDevice *d); > >> > > >> > So here is a property and it does not do anything. > >> > It makes it easier to work on series maybe, but review > >> > is harder since we do not see what it does at all. > >> > Please do not split up patches like this - you can maintain > >> > it split up in your branch if you like and merge before sending. > >> > > >> > >> Agreed, Alexandr please merge patches 4-5-6 for your next submission. > >> > >> Thanks, > >> Marcel > >> > >> > >> > > -- > >> > > 2.7.4 > > > > -- > Alexander Bezzubikov

2 1

Re: [SeaBIOS] [RFC PATCH v2 6/6] hw/pci: add hint capabilty for additional bus reservation to pcie-root-port
by Marcel Apfelbaum 25 Jul '17

25 Jul '17

On 25/07/2017 0:43, Alexander Bezzubikov wrote: > 2017-07-24 23:43 GMT+03:00 Michael S. Tsirkin <mst(a)redhat.com>: >> On Sun, Jul 23, 2017 at 01:15:43AM +0300, Aleksandr Bezzubikov wrote: >>> Signed-off-by: Aleksandr Bezzubikov <zuban32s(a)gmail.com> >>> --- >>> hw/pci-bridge/pcie_root_port.c | 5 +++++ >>> 1 file changed, 5 insertions(+) >>> >>> diff --git a/hw/pci-bridge/pcie_root_port.c b/hw/pci-bridge/pcie_root_port.c >>> index b0e49e1..ca92d85 100644 >>> --- a/hw/pci-bridge/pcie_root_port.c >>> +++ b/hw/pci-bridge/pcie_root_port.c >>> @@ -106,6 +106,11 @@ static void rp_realize(PCIDevice *d, Error **errp) >>> pcie_aer_root_init(d); >>> rp_aer_vector_update(d); >>> >>> + rc = pci_bridge_help_cap_init(d, 0, p->bus_reserve, 0, 0, 0, errp); >>> + if (rc < 0) { >>> + goto err; >>> + } >>> + >>> return; >>> >>> err: >> >> It looks like this will add the capability unconditionally to all >> pcie root ports. Two issues with it: >> 1. you can't add vendor properties to devices where vendor is >> not qemu as they might have their own concept of what it does. >> 2. this will break compatibility with old machine types, >> need to disable for these >> > > Actually the original idea was to add it for pcie-root-port excusively > (for now at least), looks like I've confused a little with files naming. Right, for the Generic PCIe Root Port and not for all the root ports. In the future we may want to add it to the PCI-brigde so we can have nested bridges, but we are not there yet. > Will add it for v3. > Thanks, Marcel >>> -- >>> 2.7.4 > > >

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