[PATCH v3 0/2] pci: reserve resources for pcie-pci-bridge to fix regressed hotplug on q35 with ACPI hotplug enabled

[Igor Mammedov]

Since QEMU-6.1, Q35 machine is using ACPI PCI hotplug by default.
However SeaBIOS did not take in account pcie-pci-bridge and treated it
as any other PCIe device which is not correct in the case of the bridge.

Patch [1/2] fixes main issue by treating the bridge as a device with
possible SHPC capability.
Patch [2/2] fixes missed IO reservation, by making sure that in the case of
the bridge firmware reserves IO resource.

Igor Mammedov (2):
  pci: reserve resources for pcie-pci-bridge to fix regressed hotplug on
    q35
  pci: let firmware reserve IO for pcie-pci-bridge

src/fw/pciinit.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

[PATCH v3 1/2] pci: reserve resources for pcie-pci-bridge to fix regressed hotplug on q35

[Igor Mammedov]

If QEMU is started with unpopulated pcie-pci-bridge with ACPI PCI
hotplug enabled (default since QEMU-6.1), hotplugging a PCI device
into one of the bridge slots fails due to lack of resources.

once linux guest is booted (test used Fedora 34), hotplug NIC from
QEMU monitor:
  (qemu) device_add rtl8139,bus=pcie-pci-bridge-0,addr=0x2

guest fails hotplug with:
  pci 0000:01:02.0: [10ec:8139] type 00 class 0x020000
  pci 0000:01:02.0: reg 0x10: [io  0x0000-0x00ff]
  pci 0000:01:02.0: reg 0x14: [mem 0x00000000-0x000000ff]
  pci 0000:01:02.0: reg 0x30: [mem 0x00000000-0x0003ffff pref]
  pci 0000:01:02.0: BAR 6: no space for [mem size 0x00040000 pref]
  pci 0000:01:02.0: BAR 6: failed to assign [mem size 0x00040000 pref]
  pci 0000:01:02.0: BAR 0: no space for [io  size 0x0100]
  pci 0000:01:02.0: BAR 0: failed to assign [io  size 0x0100]
  pci 0000:01:02.0: BAR 1: no space for [mem size 0x00000100]
  pci 0000:01:02.0: BAR 1: failed to assign [mem size 0x00000100]
  8139cp: 8139cp: 10/100 PCI Ethernet driver v1.3 (Mar 22, 2004)
  PCI Interrupt Link [GSIG] enabled at IRQ 22
  8139cp 0000:01:02.0: no MMIO resource
  8139cp: probe of 0000:01:02.0 failed with error -5

Reason for this is that commit [1] didn't take into account
pcie-pci-bridge, marking bridge as non hotpluggable instead of
handling it as possibly SHPC capable bridge.
Fix issue by checking if pcie-pci-bridge is SHPC capable and
if it is mark it as hotpluggable.

Fixes regression in QEMU-6.1 and later, since it was switched
to ACPI based PCI hotplug on Q35 by default at that time.

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2001732
[1]
Fixes: 3aa31d7d637 ("hw/pci: reserve IO and mem for pci express downstream ports with no devices attached")
Signed-off-by: Igor Mammedov [e-mail]
CC: [e-mail]
CC: [e-mail]
CC: [e-mail]
CC: [e-mail]
CC: [e-mail]
---
 src/fw/pciinit.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index d25931bb..7342d8d8 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -802,6 +802,10 @@ static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
                                           pcie_cap + PCI_EXP_FLAGS);
         u8 port_type = ((pcie_flags & PCI_EXP_FLAGS_TYPE) >>
                        (__builtin_ffs(PCI_EXP_FLAGS_TYPE) - 1));
+
+        if (port_type == PCI_EXP_TYPE_PCI_BRIDGE)
+            goto check_shpc;
+
         u8 downstream_port = (port_type == PCI_EXP_TYPE_DOWNSTREAM) ||
                              (port_type == PCI_EXP_TYPE_ROOT_PORT);
         /*
@@ -818,6 +822,7 @@ static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
         return downstream_port && slot_implemented;
     }

+check_shpc:
     shpc_cap = pci_find_capability(bus->bus_dev->bdf, PCI_CAP_ID_SHPC, 0);
     return !!shpc_cap;
 }

[PATCH v3 1/2] pci: reserve resources for pcie-pci-bridge to fix regressed hotplug on q35

[Laurent Vivier]

On 29/11/2021 12:48, Igor Mammedov wrote:
> If QEMU is started with unpopulated pcie-pci-bridge with ACPI PCI
> hotplug enabled (default since QEMU-6.1), hotplugging a PCI device
> into one of the bridge slots fails due to lack of resources.
>
> once linux guest is booted (test used Fedora 34), hotplug NIC from
> QEMU monitor:
>    (qemu) device_add rtl8139,bus=pcie-pci-bridge-0,addr=0x2
>
> guest fails hotplug with:
>    pci 0000:01:02.0: [10ec:8139] type 00 class 0x020000
>    pci 0000:01:02.0: reg 0x10: [io  0x0000-0x00ff]
>    pci 0000:01:02.0: reg 0x14: [mem 0x00000000-0x000000ff]
>    pci 0000:01:02.0: reg 0x30: [mem 0x00000000-0x0003ffff pref]
>    pci 0000:01:02.0: BAR 6: no space for [mem size 0x00040000 pref]
>    pci 0000:01:02.0: BAR 6: failed to assign [mem size 0x00040000 pref]
>    pci 0000:01:02.0: BAR 0: no space for [io  size 0x0100]
>    pci 0000:01:02.0: BAR 0: failed to assign [io  size 0x0100]
>    pci 0000:01:02.0: BAR 1: no space for [mem size 0x00000100]
>    pci 0000:01:02.0: BAR 1: failed to assign [mem size 0x00000100]
>    8139cp: 8139cp: 10/100 PCI Ethernet driver v1.3 (Mar 22, 2004)
>    PCI Interrupt Link [GSIG] enabled at IRQ 22
>    8139cp 0000:01:02.0: no MMIO resource
>    8139cp: probe of 0000:01:02.0 failed with error -5
>
> Reason for this is that commit [1] didn't take into account
> pcie-pci-bridge, marking bridge as non hotpluggable instead of
> handling it as possibly SHPC capable bridge.
> Fix issue by checking if pcie-pci-bridge is SHPC capable and
> if it is mark it as hotpluggable.
>
> Fixes regression in QEMU-6.1 and later, since it was switched
> to ACPI based PCI hotplug on Q35 by default at that time.
>
> RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2001732
> [1]
> Fixes: 3aa31d7d637 ("hw/pci: reserve IO and mem for pci express downstream ports with no devices attached")
> Signed-off-by: Igor Mammedov [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
>
> src/fw/pciinit.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
> index d25931bb..7342d8d8 100644
> --- a/src/fw/pciinit.c
> +++ b/src/fw/pciinit.c
> @@ -802,6 +802,10 @@ static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
>                                             pcie_cap + PCI_EXP_FLAGS);
>           u8 port_type = ((pcie_flags & PCI_EXP_FLAGS_TYPE) >>
>                          (__builtin_ffs(PCI_EXP_FLAGS_TYPE) - 1));
>    if (port_type == PCI_EXP_TYPE_PCI_BRIDGE)
>        goto check_shpc;
>     u8 downstream_port = (port_type == PCI_EXP_TYPE_DOWNSTREAM) ||
>                          (port_type == PCI_EXP_TYPE_ROOT_PORT);
>     /*
>
> @@ -818,6 +822,7 @@ static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
>           return downstream_port && slot_implemented;
>       }
>
> +check_shpc:
>       shpc_cap = pci_find_capability(bus->bus_dev->bdf, PCI_CAP_ID_SHPC, 0);
>       return !!shpc_cap;
>   }

Tested-by: Laurent Vivier

[PATCH v3 1/2] pci: reserve resources for pcie-pci-bridge to fix regressed hotplug on q35

[Michael S. Tsirkin]

On Mon, Nov 29, 2021 at 06:48:11AM -0500, Igor Mammedov wrote:
> If QEMU is started with unpopulated pcie-pci-bridge with ACPI PCI
> hotplug enabled (default since QEMU-6.1), hotplugging a PCI device
> into one of the bridge slots fails due to lack of resources.
>
> once linux guest is booted (test used Fedora 34), hotplug NIC from
> QEMU monitor:
>   (qemu) device_add rtl8139,bus=pcie-pci-bridge-0,addr=0x2
>
> guest fails hotplug with:
>   pci 0000:01:02.0: [10ec:8139] type 00 class 0x020000
>   pci 0000:01:02.0: reg 0x10: [io  0x0000-0x00ff]
>   pci 0000:01:02.0: reg 0x14: [mem 0x00000000-0x000000ff]
>   pci 0000:01:02.0: reg 0x30: [mem 0x00000000-0x0003ffff pref]
>   pci 0000:01:02.0: BAR 6: no space for [mem size 0x00040000 pref]
>   pci 0000:01:02.0: BAR 6: failed to assign [mem size 0x00040000 pref]
>   pci 0000:01:02.0: BAR 0: no space for [io  size 0x0100]
>   pci 0000:01:02.0: BAR 0: failed to assign [io  size 0x0100]
>   pci 0000:01:02.0: BAR 1: no space for [mem size 0x00000100]
>   pci 0000:01:02.0: BAR 1: failed to assign [mem size 0x00000100]
>   8139cp: 8139cp: 10/100 PCI Ethernet driver v1.3 (Mar 22, 2004)
>   PCI Interrupt Link [GSIG] enabled at IRQ 22
>   8139cp 0000:01:02.0: no MMIO resource
>   8139cp: probe of 0000:01:02.0 failed with error -5
>
> Reason for this is that commit [1] didn't take into account
> pcie-pci-bridge, marking bridge as non hotpluggable instead of
> handling it as possibly SHPC capable bridge.
> Fix issue by checking if pcie-pci-bridge is SHPC capable and
> if it is mark it as hotpluggable.
>
> Fixes regression in QEMU-6.1 and later, since it was switched
> to ACPI based PCI hotplug on Q35 by default at that time.
>
> RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2001732
> [1]
> Fixes: 3aa31d7d637 ("hw/pci: reserve IO and mem for pci express downstream ports with no devices attached")
> Signed-off-by: Igor Mammedov [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]

Acked-by: Michael S. Tsirkin
> src/fw/pciinit.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
> index d25931bb..7342d8d8 100644
> --- a/src/fw/pciinit.c
> +++ b/src/fw/pciinit.c
> @@ -802,6 +802,10 @@ static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
>                                            pcie_cap + PCI_EXP_FLAGS);
>          u8 port_type = ((pcie_flags & PCI_EXP_FLAGS_TYPE) >>
>                         (__builtin_ffs(PCI_EXP_FLAGS_TYPE) - 1));
>    if (port_type == PCI_EXP_TYPE_PCI_BRIDGE)
>        goto check_shpc;
>    u8 downstream_port = (port_type == PCI_EXP_TYPE_DOWNSTREAM) ||
>                         (port_type == PCI_EXP_TYPE_ROOT_PORT);
>    /*
>
> @@ -818,6 +822,7 @@ static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
>          return downstream_port && slot_implemented;
>      }
>
> +check_shpc:
>      shpc_cap = pci_find_capability(bus->bus_dev->bdf, PCI_CAP_ID_SHPC, 0);
>      return !!shpc_cap;
>  }
> -- 
> 2.27.0

[PATCH v3 2/2] pci: let firmware reserve IO for pcie-pci-bridge

[Igor Mammedov]

With [1] patch hotplug of rtl8139 succeeds, with caveat that it
fails to initialize IO bar, which is caused by [2] that makes
firmware skip IO reservation for any PCIe device, which isn't
correct in case of pcie-pci-bridge.
Fix it by exposing hotplug type and making IO resource optional
only if PCIe hotplug is in use.

[1]
 "pci: reserve resources for pcie-pci-bridge to fix regressed hotplug on q35"
[2]
Fixes: 76327b9f32a ("fw/pci: do not automatically allocate IO region for PCIe bridges")
Signed-off-by: Igor Mammedov [e-mail]
CC: [e-mail]
CC: [e-mail]
CC: [e-mail]
CC: [e-mail]
CC: [e-mail]
---
 src/fw/pciinit.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index 7342d8d8..badf13d3 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -793,7 +793,13 @@ pci_region_create_entry(struct pci_bus *bus, struct pci_device *dev,
     return entry;
 }

-static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
+typedef enum hotplug_type_t {
+    HOTPLUG_NO_SUPPORTED = 0,
+    HOTPLUG_PCIE,
+    HOTPLUG_SHPC
+} hotplug_type_t;
+
+static hotplug_type_t pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
 {
     u8 shpc_cap;

@@ -819,12 +825,13 @@ static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
          */
         u16 slot_implemented = pcie_flags & PCI_EXP_FLAGS_SLOT;

-        return downstream_port && slot_implemented;
+        return downstream_port && slot_implemented ?
+            HOTPLUG_PCIE : HOTPLUG_NO_SUPPORTED;
     }

check_shpc:
     shpc_cap = pci_find_capability(bus->bus_dev->bdf, PCI_CAP_ID_SHPC, 0);
-    return !!shpc_cap;
+    return !!shpc_cap ? HOTPLUG_SHPC : HOTPLUG_NO_SUPPORTED;
 }

/* Test whether bridge support forwarding of transactions
@@ -909,7 +916,7 @@ static int pci_bios_check_devices(struct pci_bus *busses)
         u8 pcie_cap = pci_find_capability(bdf, PCI_CAP_ID_EXP, 0);
         u8 qemu_cap = pci_find_resource_reserve_capability(bdf);

-        int hotplug_support = pci_bus_hotplug_support(s, pcie_cap);
+        hotplug_type_t hotplug_support = pci_bus_hotplug_support(s, pcie_cap);
         for (type = 0; type < PCI_REGION_TYPE_COUNT; type++) {
             u64 align = (type == PCI_REGION_TYPE_IO) ?
                 PCI_BRIDGE_IO_MIN : PCI_BRIDGE_MEM_MIN;
@@ -953,7 +960,9 @@ static int pci_bios_check_devices(struct pci_bus *busses)
             if (pci_region_align(&s->r[type]) > align)
                  align = pci_region_align(&s->r[type]);
             u64 sum = pci_region_sum(&s->r[type]);
-            int resource_optional = pcie_cap && (type == PCI_REGION_TYPE_IO);
+            int resource_optional = 0;
+            if (hotplug_support == HOTPLUG_PCIE)
+                resource_optional = pcie_cap && (type == PCI_REGION_TYPE_IO);
             if (!sum && hotplug_support && !resource_optional)
                 sum = align; /* reserve min size for hot-plug */
             if (size > sum) {

[PATCH v3 2/2] pci: let firmware reserve IO for pcie-pci-bridge

[Laurent Vivier]

On 29/11/2021 12:48, Igor Mammedov wrote:
> With [1] patch hotplug of rtl8139 succeeds, with caveat that it
> fails to initialize IO bar, which is caused by [2] that makes
> firmware skip IO reservation for any PCIe device, which isn't
> correct in case of pcie-pci-bridge.
> Fix it by exposing hotplug type and making IO resource optional
> only if PCIe hotplug is in use.
>
> [1]
>   "pci: reserve resources for pcie-pci-bridge to fix regressed hotplug on q35"
> [2]
> Fixes: 76327b9f32a ("fw/pci: do not automatically allocate IO region for PCIe bridges")
> Signed-off-by: Igor Mammedov [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
>
> src/fw/pciinit.c | 19 ++++++++++++++-----
>   1 file changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
> index 7342d8d8..badf13d3 100644
> --- a/src/fw/pciinit.c
> +++ b/src/fw/pciinit.c
> @@ -793,7 +793,13 @@ pci_region_create_entry(struct pci_bus *bus, struct pci_device *dev,
>       return entry;
>   }
>
> -static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
> +typedef enum hotplug_type_t {
> HOTPLUG_NO_SUPPORTED = 0,
> HOTPLUG_PCIE,
> HOTPLUG_SHPC
>
> +} hotplug_type_t;
>
> +static hotplug_type_t pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
>   {
>       u8 shpc_cap;
>
> @@ -819,12 +825,13 @@ static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
>            */
>           u16 slot_implemented = pcie_flags & PCI_EXP_FLAGS_SLOT;
>    return downstream_port && slot_implemented;
>    return downstream_port && slot_implemented ?
>        HOTPLUG_PCIE : HOTPLUG_NO_SUPPORTED;
> }
>
> check_shpc:
>     shpc_cap = pci_find_capability(bus->bus_dev->bdf, PCI_CAP_ID_SHPC, 0);
> return !!shpc_cap;
>
> return !!shpc_cap ? HOTPLUG_SHPC : HOTPLUG_NO_SUPPORTED;
> }
>
> /* Test whether bridge support forwarding of transactions
>
> @@ -909,7 +916,7 @@ static int pci_bios_check_devices(struct pci_bus *busses)
>           u8 pcie_cap = pci_find_capability(bdf, PCI_CAP_ID_EXP, 0);
>           u8 qemu_cap = pci_find_resource_reserve_capability(bdf);
>    int hotplug_support = pci_bus_hotplug_support(s, pcie_cap);
>    hotplug_type_t hotplug_support = pci_bus_hotplug_support(s, pcie_cap);
>     for (type = 0; type < PCI_REGION_TYPE_COUNT; type++) {
>         u64 align = (type == PCI_REGION_TYPE_IO) ?
>             PCI_BRIDGE_IO_MIN : PCI_BRIDGE_MEM_MIN;
>
> @@ -953,7 +960,9 @@ static int pci_bios_check_devices(struct pci_bus *busses)
>               if (pci_region_align(&s->r[type]) > align)
>                    align = pci_region_align(&s->r[type]);
>               u64 sum = pci_region_sum(&s->r[type]);
>        int resource_optional = pcie_cap && (type == PCI_REGION_TYPE_IO);
>        int resource_optional = 0;
>        if (hotplug_support == HOTPLUG_PCIE)
>            resource_optional = pcie_cap && (type == PCI_REGION_TYPE_IO);
>         if (!sum && hotplug_support && !resource_optional)
>             sum = align; /* reserve min size for hot-plug */
>         if (size > sum) {

Tested-by: Laurent Vivier

[PATCH v3 2/2] pci: let firmware reserve IO for pcie-pci-bridge

[Michael S. Tsirkin]

On Mon, Nov 29, 2021 at 06:48:12AM -0500, Igor Mammedov wrote:
> With [1] patch hotplug of rtl8139 succeeds, with caveat that it
> fails to initialize IO bar, which is caused by [2] that makes
> firmware skip IO reservation for any PCIe device, which isn't
> correct in case of pcie-pci-bridge.
> Fix it by exposing hotplug type and making IO resource optional
> only if PCIe hotplug is in use.
>
> [1]
>  "pci: reserve resources for pcie-pci-bridge to fix regressed hotplug on q35"
> [2]
> Fixes: 76327b9f32a ("fw/pci: do not automatically allocate IO region for PCIe bridges")
> Signed-off-by: Igor Mammedov [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]
> CC: [e-mail]

Acked-by: Michael S. Tsirkin
> src/fw/pciinit.c | 19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
> index 7342d8d8..badf13d3 100644
> --- a/src/fw/pciinit.c
> +++ b/src/fw/pciinit.c
> @@ -793,7 +793,13 @@ pci_region_create_entry(struct pci_bus *bus, struct pci_device *dev,
>      return entry;
>  }
>
> -static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
> +typedef enum hotplug_type_t {
> HOTPLUG_NO_SUPPORTED = 0,
> HOTPLUG_PCIE,
> HOTPLUG_SHPC
>
> +} hotplug_type_t;
>
> +static hotplug_type_t pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
>  {
>      u8 shpc_cap;
>
> @@ -819,12 +825,13 @@ static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
>           */
>          u16 slot_implemented = pcie_flags & PCI_EXP_FLAGS_SLOT;
>    return downstream_port && slot_implemented;
>    return downstream_port && slot_implemented ?
>        HOTPLUG_PCIE : HOTPLUG_NO_SUPPORTED;
> }
>
> check_shpc:
>      shpc_cap = pci_find_capability(bus->bus_dev->bdf, PCI_CAP_ID_SHPC, 0);
> return !!shpc_cap;
> return !!shpc_cap ? HOTPLUG_SHPC : HOTPLUG_NO_SUPPORTED;
>
> }
>
> /* Test whether bridge support forwarding of transactions
> @@ -909,7 +916,7 @@ static int pci_bios_check_devices(struct pci_bus *busses)
>          u8 pcie_cap = pci_find_capability(bdf, PCI_CAP_ID_EXP, 0);
>          u8 qemu_cap = pci_find_resource_reserve_capability(bdf);
>    int hotplug_support = pci_bus_hotplug_support(s, pcie_cap);
>    hotplug_type_t hotplug_support = pci_bus_hotplug_support(s, pcie_cap);
>    for (type = 0; type < PCI_REGION_TYPE_COUNT; type++) {
>        u64 align = (type == PCI_REGION_TYPE_IO) ?
>            PCI_BRIDGE_IO_MIN : PCI_BRIDGE_MEM_MIN;
>
> @@ -953,7 +960,9 @@ static int pci_bios_check_devices(struct pci_bus *busses)
>              if (pci_region_align(&s->r[type]) > align)
>                   align = pci_region_align(&s->r[type]);
>              u64 sum = pci_region_sum(&s->r[type]);
>        int resource_optional = pcie_cap && (type == PCI_REGION_TYPE_IO);
>        int resource_optional = 0;
>        if (hotplug_support == HOTPLUG_PCIE)
>            resource_optional = pcie_cap && (type == PCI_REGION_TYPE_IO);
>        if (!sum && hotplug_support && !resource_optional)
>            sum = align; /* reserve min size for hot-plug */
>        if (size > sum) {

[PATCH v3 2/2] pci: let firmware reserve IO for pcie-pci-bridge

[Peter Stuge]

Igor Mammedov wrote:
> +++ b/src/fw/pciinit.c

..
> @@ -819,12 +825,13 @@ static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
>           */
>          u16 slot_implemented = pcie_flags & PCI_EXP_FLAGS_SLOT;
>    return downstream_port && slot_implemented;
>    return downstream_port && slot_implemented ?
>        HOTPLUG_PCIE : HOTPLUG_NO_SUPPORTED;
> }
>
> check_shpc:
>      shpc_cap = pci_find_capability(bus->bus_dev->bdf, PCI_CAP_ID_SHPC, 0);
> return !!shpc_cap;
> return !!shpc_cap ? HOTPLUG_SHPC : HOTPLUG_NO_SUPPORTED;

Maybe remove !! here.

//Peter

[Kevin O'Connor]

On Mon, Nov 29, 2021 at 06:48:10AM -0500, Igor Mammedov wrote:
> Since QEMU-6.1, Q35 machine is using ACPI PCI hotplug by default.
> However SeaBIOS did not take in account pcie-pci-bridge and treated it
> as any other PCIe device which is not correct in the case of the bridge.

Thanks.  It looks fine to me.  I'll give another day or so for others
to comment, but otherwise will plan to commit.

-Kevin

[Kevin O'Connor]

On Mon, Nov 29, 2021 at 06:48:10AM -0500, Igor Mammedov wrote:
> Since QEMU-6.1, Q35 machine is using ACPI PCI hotplug by default.
> However SeaBIOS did not take in account pcie-pci-bridge and treated it
> as any other PCIe device which is not correct in the case of the bridge.
>
> Patch [1/2] fixes main issue by treating the bridge as a device with
> possible SHPC capability.
> Patch [2/2] fixes missed IO reservation, by making sure that in the case of
> the bridge firmware reserves IO resource.

Thanks.  I committed this series.

-Kevin