[PATCH v4 0/3] Allow RedHat PCI bridges reserve more buses than necessary during init

[Aleksandr Bezzubikov]

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 (as well as IO/MEM/PREF space limit hints) 
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 series "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. And
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 v3->v4:
1. Use all QEMU PCI capability fields - addresses Michael's comment
2. Changes of the capability layout (QEMU side has the same changes):
    - change reservation fields types: bus_res - uint32_t, others - uint64_t
    - interpret -1 value as 'ignore'

Changes v2->v3:
1. Merge commit 2 (Red Hat vendor ID) into commit 4 - addresses Marcel's comment,
    and add Generic PCIE Root Port device ID - addresses Michael's comment.
2. Changes of the capability layout  (QEMU side has the same changes):
    - add 'type' field to distinguish multiple 
    	RedHat-specific capabilities - addresses Michael's comment
    - do not mimiс PCI Config space register layout, but use mutually exclusive differently
    	sized fields for IO and prefetchable memory limits - addresses Laszlo's comment
    - use defines instead of structure and offsetof - addresses Michael's comment
3. Interpret 'bus_reserve' field as a minimum necessary
     range to reserve - addresses Gerd's comment
4. pci_find_capability moved to pci.c - addresses Kevin's comment
5. Move capability layout header to src/fw/dev-pci.h - addresses Kevin's comment
6. Add the capability documentation - addresses Michael's comment
7. Add capability length and bus_reserve field sanity checks - addresses Michael's comment

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 (3):
  pci: refactor pci_find_capapibilty to get bdf as the first argument
    instead of the whole pci_device
  pci: add QEMU-specific PCI capability structure
  pci: enable RedHat PCI bridges to reserve additional buses on PCI init

src/fw/dev-pci.h    | 50 ++++++++++++++++++++++++++++++++++++
 src/fw/pciinit.c    | 73 ++++++++++++++++++++++++++++++++++++++++++++++++-----
 src/hw/pci.c        | 25 ++++++++++++++++++
 src/hw/pci.h        |  1 +
 src/hw/pci_ids.h    |  3 +++
 src/hw/pcidevice.c  | 24 ------------------
 src/hw/pcidevice.h  |  1 -
 src/hw/virtio-pci.c |  6 ++---
 8 files changed, 149 insertions(+), 34 deletions(-)
 create mode 100644 src/fw/dev-pci.h

[PATCH v4 1/3] pci: refactor pci_find_capapibilty to get bdf as the first argument instead of the whole pci_device

[Aleksandr Bezzubikov]

Refactor pci_find_capability function to get bdf instead of
a whole pci_device* as the only necessary field for this function
is still bdf.

Signed-off-by: Aleksandr Bezzubikov 
Reviewed-by: Marcel Apfelbaum 
---
 src/fw/pciinit.c    |  4 ++--
 src/hw/pci.c        | 25 +++++++++++++++++++++++++
 src/hw/pci.h        |  1 +
 src/hw/pcidevice.c  | 24 ------------------------
 src/hw/pcidevice.h  |  1 -
 src/hw/virtio-pci.c |  6 +++---
 6 files changed, 31 insertions(+), 30 deletions(-)

diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index 08221e6..864954f 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -762,7 +762,7 @@ static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
         return downstream_port && slot_implemented;
     }

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

@@ -844,7 +844,7 @@ static int pci_bios_check_devices(struct pci_bus *busses)
              */
             parent = &busses[0];
         int type;
-        u8 pcie_cap = pci_find_capability(s->bus_dev, PCI_CAP_ID_EXP, 0);
+        u8 pcie_cap = pci_find_capability(s->bus_dev->bdf, PCI_CAP_ID_EXP, 0);
         int 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) ?
diff --git a/src/hw/pci.c b/src/hw/pci.c
index 8e3d617..50d9d2d 100644
--- a/src/hw/pci.c
+++ b/src/hw/pci.c
@@ -58,6 +58,30 @@ pci_config_maskw(u16 bdf, u32 addr, u16 off, u16 on)
     pci_config_writew(bdf, addr, val);
 }

+u8 pci_find_capability(u16 bdf, u8 cap_id, u8 cap)
+{
+    int i;
+    u16 status = pci_config_readw(bdf, PCI_STATUS);
+
+    if (!(status & PCI_STATUS_CAP_LIST))
+        return 0;
+
+    if (cap == 0) {
+        /* find first */
+        cap = pci_config_readb(bdf, PCI_CAPABILITY_LIST);
+    } else {
+        /* find next */
+        cap = pci_config_readb(bdf, cap + PCI_CAP_LIST_NEXT);
+    }
+    for (i = 0; cap && i <= 0xff; i++) {
+        if (pci_config_readb(bdf, cap + PCI_CAP_LIST_ID) == cap_id)
+            return cap;
+        cap = pci_config_readb(bdf, cap + PCI_CAP_LIST_NEXT);
+    }
+
+    return 0;
+}
+
 // Helper function for foreachbdf() macro - return next device
 int
 pci_next(int bdf, int bus)
@@ -107,3 +131,4 @@ pci_reboot(void)
     outb(v|6, PORT_PCI_REBOOT); /* Actually do the reset */
     udelay(50);
 }
+
diff --git a/src/hw/pci.h b/src/hw/pci.h
index ee6e196..2e30e28 100644
--- a/src/hw/pci.h
+++ b/src/hw/pci.h
@@ -39,6 +39,7 @@ u32 pci_config_readl(u16 bdf, u32 addr);
 u16 pci_config_readw(u16 bdf, u32 addr);
 u8 pci_config_readb(u16 bdf, u32 addr);
 void pci_config_maskw(u16 bdf, u32 addr, u16 off, u16 on);
+u8 pci_find_capability(u16 bdf, u8 cap_id, u8 cap);
 int pci_next(int bdf, int bus);
 int pci_probe_host(void);
 void pci_reboot(void);
diff --git a/src/hw/pcidevice.c b/src/hw/pcidevice.c
index cfebf66..8853cf7 100644
--- a/src/hw/pcidevice.c
+++ b/src/hw/pcidevice.c
@@ -134,30 +134,6 @@ pci_find_init_device(const struct pci_device_id *ids, void *arg)
     return NULL;
 }

-u8 pci_find_capability(struct pci_device *pci, u8 cap_id, u8 cap)
-{
-    int i;
-    u16 status = pci_config_readw(pci->bdf, PCI_STATUS);
-
-    if (!(status & PCI_STATUS_CAP_LIST))
-        return 0;
-
-    if (cap == 0) {
-        /* find first */
-        cap = pci_config_readb(pci->bdf, PCI_CAPABILITY_LIST);
-    } else {
-        /* find next */
-        cap = pci_config_readb(pci->bdf, cap + PCI_CAP_LIST_NEXT);
-    }
-    for (i = 0; cap && i <= 0xff; i++) {
-        if (pci_config_readb(pci->bdf, cap + PCI_CAP_LIST_ID) == cap_id)
-            return cap;
-        cap = pci_config_readb(pci->bdf, cap + PCI_CAP_LIST_NEXT);
-    }
-
-    return 0;
-}
-
 // Enable PCI bus-mastering (ie, DMA) support on a pci device
 void
 pci_enable_busmaster(struct pci_device *pci)
diff --git a/src/hw/pcidevice.h b/src/hw/pcidevice.h
index 354b549..225d545 100644
--- a/src/hw/pcidevice.h
+++ b/src/hw/pcidevice.h
@@ -69,7 +69,6 @@ int pci_init_device(const struct pci_device_id *ids
                     , struct pci_device *pci, void *arg);
 struct pci_device *pci_find_init_device(const struct pci_device_id *ids
                                         , void *arg);
-u8 pci_find_capability(struct pci_device *pci, u8 cap_id, u8 cap);
 void pci_enable_busmaster(struct pci_device *pci);
 u16 pci_enable_iobar(struct pci_device *pci, u32 addr);
 void *pci_enable_membar(struct pci_device *pci, u32 addr);
diff --git a/src/hw/virtio-pci.c b/src/hw/virtio-pci.c
index e5c2c33..96f9c6b 100644
--- a/src/hw/virtio-pci.c
+++ b/src/hw/virtio-pci.c
@@ -19,7 +19,7 @@
 #include "malloc.h" // free
 #include "output.h" // dprintf
 #include "pci.h" // pci_config_readl
-#include "pcidevice.h" // pci_find_capability
+#include "pcidevice.h" // struct pci_device
 #include "pci_regs.h" // PCI_BASE_ADDRESS_0
 #include "string.h" // memset
 #include "virtio-pci.h"
@@ -381,7 +381,7 @@ fail:

void vp_init_simple(struct vp_device *vp, struct pci_device *pci)
 {
-    u8 cap = pci_find_capability(pci, PCI_CAP_ID_VNDR, 0);
+    u8 cap = pci_find_capability(pci->bdf, PCI_CAP_ID_VNDR, 0);
     struct vp_cap *vp_cap;
     const char *mode;
     u32 offset, base, mul;
@@ -479,7 +479,7 @@ void vp_init_simple(struct vp_device *vp, struct pci_device *pci)
                     vp_cap->cap, type, vp_cap->bar, addr, offset, mode);
         }

-        cap = pci_find_capability(pci, PCI_CAP_ID_VNDR, cap);
+        cap = pci_find_capability(pci->bdf, PCI_CAP_ID_VNDR, cap);
     }

if (vp->common.cap && vp->notify.cap && vp->isr.cap && vp->device.cap) {

[PATCH v4 2/3] pci: add QEMU-specific PCI capability structure

[Aleksandr Bezzubikov]

On PCI init PCI bridge devices may need some
extra info about bus number to reserve, IO, memory and
prefetchable memory limits. QEMU can provide this
with special vendor-specific PCI capability.

This capability is intended to be used only
for Red Hat PCI bridges, i.e. QEMU cooperation.

Signed-off-by: Aleksandr Bezzubikov 
---
 src/fw/dev-pci.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 src/fw/dev-pci.h

diff --git a/src/fw/dev-pci.h b/src/fw/dev-pci.h
new file mode 100644
index 0000000..2c8ddb0
--- /dev/null
+++ b/src/fw/dev-pci.h
@@ -0,0 +1,50 @@
+#ifndef _PCI_CAP_H
+#define _PCI_CAP_H
+
+#include "types.h"
+
+/*
+
+QEMU-specific vendor(Red Hat)-specific capability.
+It's intended to provide some hints for firmware to init PCI devices.
+
+Its structure is shown below:
+
+Header:
+
+u8 id;       Standard PCI Capability Header field
+u8 next;     Standard PCI Capability Header field
+u8 len;      Standard PCI Capability Header field
+u8 type;     Red Hat vendor-specific capability type:
+               now only REDHAT_CAP_TYP_QEMU=1 exists
+Data:
+
+u32 bus_res;            minimum bus number to reserve;
+                        this is necessary for PCI Express Root Ports
+                        to support PCIE-to-PCI bridge hotplug
+u64 io;                 IO space to reserve
+u64 mem;                non-prefetchable memory space to reserve
+u64 prefetchable_mem;   prefetchable memory space to reserve
+
+If any field value in Data section is -1,
+it means that such kind of reservation
+is not needed and must be ignored.
+
+*/
+
+/* Offset of vendor-specific capability type field */
+#define PCI_CAP_REDHAT_TYPE  3
+
+/* List of valid Red Hat vendor-specific capability types */
+#define REDHAT_CAP_TYPE_QEMU    1
+
+
+/* Offsets of QEMU capability fields */
+#define QEMU_PCI_CAP_BUS_RES        4
+#define QEMU_PCI_CAP_LIMITS_OFFSET  8
+#define QEMU_PCI_CAP_IO             8
+#define QEMU_PCI_CAP_MEM            16
+#define QEMU_PCI_CAP_PREF_MEM       24
+#define QEMU_PCI_CAP_SIZE           32
+
+#endif /* _PCI_CAP_H */

[PATCH v4 2/3] pci: add QEMU-specific PCI capability structure

[Marcel Apfelbaum]

On 05/08/2017 23:29, Aleksandr Bezzubikov wrote:
> On PCI init PCI bridge devices may need some
> extra info about bus number to reserve, IO, memory and
> prefetchable memory limits. QEMU can provide this
> with special vendor-specific PCI capability.
>
> This capability is intended to be used only
> for Red Hat PCI bridges, i.e. QEMU cooperation.
> Signed-off-by: Aleksandr Bezzubikov
>
> src/fw/dev-pci.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 50 insertions(+)
>   create mode 100644 src/fw/dev-pci.h
>
> diff --git a/src/fw/dev-pci.h b/src/fw/dev-pci.h
> new file mode 100644
> index 0000000..2c8ddb0

Hi Aleksandr,
> --- /dev/null
> +++ b/src/fw/dev-pci.h
> @@ -0,0 +1,50 @@
> +#ifndef _PCI_CAP_H
> +#define _PCI_CAP_H
>
> +#include "types.h"
>
> +/*

Please use the standard comment:

/*
  *
  *
  */
> +QEMU-specific vendor(Red Hat)-specific capability.
> +It's intended to provide some hints for firmware to init PCI devices.
>
> +Its structure is shown below:
>
> +Header:
>
> +u8 id;       Standard PCI Capability Header field
> +u8 next;     Standard PCI Capability Header field
> +u8 len;      Standard PCI Capability Header field
> +u8 type;     Red Hat vendor-specific capability type:
>           now only REDHAT_CAP_TYP_QEMU=1 exists

Typo o the line before, but I think you don't need it there.
> +Data:
>
> +u32 bus_res;            minimum bus number to reserve;
>                    this is necessary for PCI Express Root Ports
>                    to support PCIE-to-PCI bridge hotplug

I would add a broader class of usage:
      necessary for nesting PCI bridges hotplug.
> +u64 io;                 IO space to reserve
> +u64 mem;                non-prefetchable memory space to reserve
> +u64 prefetchable_mem;   prefetchable memory space to reserve

Layout looks good to me.
> +If any field value in Data section is -1,
> +it means that such kind of reservation
> +is not needed and must be ignored.

-1 is not a valid value for unsigned fields, you may
want to say 0xff..f or some other way.
> +*/
>
> +/* Offset of vendor-specific capability type field */
> +#define PCI_CAP_REDHAT_TYPE  3

May I ask why why '3'? I am not against it, I just
want to understand the number.
> +/* List of valid Red Hat vendor-specific capability types */
> +#define REDHAT_CAP_TYPE_QEMU    1

I think I pointed this in another thread, the name is
too vague, please change it to something like:
    REDHAT_CAP_RES_RESERVE_QEMU
that narrows down the intend.
> +/* Offsets of QEMU capability fields */
> +#define QEMU_PCI_CAP_BUS_RES        4
> +#define QEMU_PCI_CAP_LIMITS_OFFSET  8
> +#define QEMU_PCI_CAP_IO             8
> +#define QEMU_PCI_CAP_MEM            16
> +#define QEMU_PCI_CAP_PREF_MEM       24
> +#define QEMU_PCI_CAP_SIZE           32
>
> +#endif /* _PCI_CAP_H */

The layout looks good to me.

Thanks,
Marcel

[PATCH v4 2/3] pci: add QEMU-specific PCI capability structure

[Alexander Bezzubikov]

2017-08-07 18:52 GMT+03:00 Marcel Apfelbaum :
> On 05/08/2017 23:29, Aleksandr Bezzubikov wrote:
> > On PCI init PCI bridge devices may need some
> > extra info about bus number to reserve, IO, memory and
> > prefetchable memory limits. QEMU can provide this
> > with special vendor-specific PCI capability.
> >
> > This capability is intended to be used only
> > for Red Hat PCI bridges, i.e. QEMU cooperation.
> > Signed-off-by: Aleksandr Bezzubikov
> >
> > src/fw/dev-pci.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 50 insertions(+)
> >   create mode 100644 src/fw/dev-pci.h
> >
> > diff --git a/src/fw/dev-pci.h b/src/fw/dev-pci.h
> > new file mode 100644
> > index 0000000..2c8ddb0
>
> Hi Aleksandr,

Hi Marcel,
> > --- /dev/null
> > +++ b/src/fw/dev-pci.h
> > @@ -0,0 +1,50 @@
> > +#ifndef _PCI_CAP_H
> > +#define _PCI_CAP_H
> >
> > +#include "types.h"
> >
> > +/*
>
> Please use the standard comment:
>
> /*
>
> */
> > +QEMU-specific vendor(Red Hat)-specific capability.
> > +It's intended to provide some hints for firmware to init PCI devices.
> >
> > +Its structure is shown below:
> >
> > +Header:
> >
> > +u8 id;       Standard PCI Capability Header field
> > +u8 next;     Standard PCI Capability Header field
> > +u8 len;      Standard PCI Capability Header field
> > +u8 type;     Red Hat vendor-specific capability type:
> >           now only REDHAT_CAP_TYP_QEMU=1 exists
>
> Typo o the line before, but I think you don't need it there.
> > +Data:
> >
> > +u32 bus_res;            minimum bus number to reserve;
> >                    this is necessary for PCI Express Root Ports
> >                    to support PCIE-to-PCI bridge hotplug
>
> I would add a broader class of usage:
>      necessary for nesting PCI bridges hotplug.
> > +u64 io;                 IO space to reserve
> > +u64 mem;                non-prefetchable memory space to reserve
> > +u64 prefetchable_mem;   prefetchable memory space to reserve
>
> Layout looks good to me.
> > +If any field value in Data section is -1,
> > +it means that such kind of reservation
> > +is not needed and must be ignored.
>
> -1 is not a valid value for unsigned fields, you may
> want to say 0xff..f or some other way.

I meant cast to unsigned here (because we still use unsigned types),
but if it can mislead someone I will change this.
> > +*/
> >
> > +/* Offset of vendor-specific capability type field */
> > +#define PCI_CAP_REDHAT_TYPE  3
>
> May I ask why why '3'? I am not against it, I just
> want to understand the number.

This is actually an offset to this field
> > +/* List of valid Red Hat vendor-specific capability types */
> > +#define REDHAT_CAP_TYPE_QEMU    1
>
> I think I pointed this in another thread, the name is
> too vague, please change it to something like:
>    REDHAT_CAP_RES_RESERVE_QEMU
> that narrows down the intend.

What does the first 'RES' mean?
> > +/* Offsets of QEMU capability fields */
> > +#define QEMU_PCI_CAP_BUS_RES        4
> > +#define QEMU_PCI_CAP_LIMITS_OFFSET  8
> > +#define QEMU_PCI_CAP_IO             8
> > +#define QEMU_PCI_CAP_MEM            16
> > +#define QEMU_PCI_CAP_PREF_MEM       24
> > +#define QEMU_PCI_CAP_SIZE           32
> >
> > +#endif /* _PCI_CAP_H */
>
> The layout looks good to me.
>
> Thanks,
> Marcel

[PATCH v4 3/3] pci: enable RedHat PCI bridges to reserve additional buses on PCI init

[Aleksandr Bezzubikov]

In case of Red Hat Generic PCIE Root Port reserve additional buses,
which number is provided in a vendor-specific capability.

Signed-off-by: Aleksandr Bezzubikov 
---
 src/fw/pciinit.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++----
 src/hw/pci_ids.h |  3 +++
 2 files changed, 68 insertions(+), 4 deletions(-)

diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index 864954f..d241d66 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -15,6 +15,7 @@
 #include "hw/pcidevice.h" // pci_probe_devices
 #include "hw/pci_ids.h" // PCI_VENDOR_ID_INTEL
 #include "hw/pci_regs.h" // PCI_COMMAND
+#include "fw/dev-pci.h" // qemu_pci_cap
 #include "list.h" // struct hlist_node
 #include "malloc.h" // free
 #include "output.h" // dprintf
@@ -578,9 +579,42 @@ pci_bios_init_bus_rec(int bus, u8 *pci_bus)
         pci_bios_init_bus_rec(secbus, pci_bus);

if (subbus != *pci_bus) {
+            u8 res_bus = 0;
+            if (pci_config_readw(bdf, PCI_VENDOR_ID) == PCI_VENDOR_ID_REDHAT &&
+                    pci_config_readw(bdf, PCI_DEVICE_ID) ==
+                            PCI_DEVICE_ID_REDHAT_ROOT_PORT) {
+                u8 cap;
+                do {
+                    cap = pci_find_capability(bdf, PCI_CAP_ID_VNDR, 0);
+                } while (cap &&
+                         pci_config_readb(bdf, cap + PCI_CAP_REDHAT_TYPE) !=
+                                REDHAT_CAP_TYPE_QEMU);
+                if (cap) {
+                    u8 cap_len = pci_config_readb(bdf, cap + PCI_CAP_FLAGS);
+                    if (cap_len != QEMU_PCI_CAP_SIZE) {
+                        dprintf(1, "PCI: QEMU cap length %d is invalid\n",
+                                cap_len);
+                    } else {
+                        u32 tmp_res_bus = pci_config_readl(bdf,
+                                                   cap + QEMU_PCI_CAP_BUS_RES);
+                        if (tmp_res_bus != (u32)-1) {
+                            res_bus = tmp_res_bus & 0xFF;
+                            if ((u8)(res_bus + secbus) < secbus ||
+                                (u8)(res_bus + secbus) < res_bus) {
+                                dprintf(1, "PCI: bus_reserve value %d is invalid\n",
+                                        res_bus);
+                                res_bus = 0;
+                            }
+                        }
+                    }
+                }
+                res_bus = (*pci_bus > secbus + res_bus) ? *pci_bus
+                                                      : secbus + res_bus;
+            }
             dprintf(1, "PCI: subordinate bus = 0x%x -> 0x%x\n",
-                    subbus, *pci_bus);
-            subbus = *pci_bus;
+                    subbus, res_bus);
+            subbus = res_bus;
+            *pci_bus = res_bus;
         } else {
             dprintf(1, "PCI: subordinate bus = 0x%x\n", subbus);
         }
@@ -951,11 +985,38 @@ pci_region_map_one_entry(struct pci_region_entry *entry, u64 addr)

u16 bdf = entry->dev->bdf;
     u64 limit = addr + entry->size - 1;
+
+    if (pci_config_readw(bdf, PCI_VENDOR_ID) == PCI_VENDOR_ID_REDHAT &&
+            pci_config_readw(bdf, PCI_DEVICE_ID) ==
+                    PCI_DEVICE_ID_REDHAT_ROOT_PORT) {
+        u8 cap;
+        do {
+            cap = pci_find_capability(bdf, PCI_CAP_ID_VNDR, 0);
+        } while (cap &&
+                 pci_config_readb(bdf, cap + PCI_CAP_REDHAT_TYPE) !=
+                        REDHAT_CAP_TYPE_QEMU);
+        if (cap) {
+            u8 cap_len = pci_config_readb(bdf, cap + PCI_CAP_FLAGS);
+            if (cap_len != QEMU_PCI_CAP_SIZE) {
+                dprintf(1, "PCI: QEMU cap length %d is invalid\n",
+                        cap_len);
+            } else {
+                u32 offset = cap + QEMU_PCI_CAP_LIMITS_OFFSET + entry->type * 8;
+                u64 tmp_limit = (pci_config_readl(bdf, offset) |
+                            (u64)pci_config_readl(bdf, offset + 4) << 32);
+                if (tmp_limit != (u64)-1) {
+                    tmp_limit += addr - 1;
+                    limit = (limit > tmp_limit) ? limit : tmp_limit;
+                }
+            }
+        }
+    }
+
     if (entry->type == PCI_REGION_TYPE_IO) {
         pci_config_writeb(bdf, PCI_IO_BASE, addr >> PCI_IO_SHIFT);
-        pci_config_writew(bdf, PCI_IO_BASE_UPPER16, 0);
+        pci_config_writew(bdf, PCI_IO_BASE_UPPER16, limit >> 16);
         pci_config_writeb(bdf, PCI_IO_LIMIT, limit >> PCI_IO_SHIFT);
-        pci_config_writew(bdf, PCI_IO_LIMIT_UPPER16, 0);
+        pci_config_writew(bdf, PCI_IO_LIMIT_UPPER16, limit >> 16);
     }
     if (entry->type == PCI_REGION_TYPE_MEM) {
         pci_config_writew(bdf, PCI_MEMORY_BASE, addr >> PCI_MEMORY_SHIFT);
diff --git a/src/hw/pci_ids.h b/src/hw/pci_ids.h
index 4ac73b4..38fa2ca 100644
--- a/src/hw/pci_ids.h
+++ b/src/hw/pci_ids.h
@@ -2263,6 +2263,9 @@
 #define PCI_DEVICE_ID_KORENIX_JETCARDF0	0x1600
 #define PCI_DEVICE_ID_KORENIX_JETCARDF1	0x16ff

+#define PCI_VENDOR_ID_REDHAT		0x1b36
+#define PCI_DEVICE_ID_REDHAT_ROOT_PORT	0x000C
+
 #define PCI_VENDOR_ID_TEKRAM		0x1de1
 #define PCI_DEVICE_ID_TEKRAM_DC290	0xdc29

[PATCH v4 3/3] pci: enable RedHat PCI bridges to reserve additional buses on PCI init

[Marcel Apfelbaum]

On 05/08/2017 23:29, Aleksandr Bezzubikov wrote:
> In case of Red Hat Generic PCIE Root Port reserve additional buses,
> which number is provided in a vendor-specific capability.

Hi Aleksandr,

It seems the subject/commit description does not cover
all that the patch does, not it also deals with other resources
as well.
> Signed-off-by: Aleksandr Bezzubikov
>
> src/fw/pciinit.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++----
>   src/hw/pci_ids.h |  3 +++
>   2 files changed, 68 insertions(+), 4 deletions(-)
>
> diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
> index 864954f..d241d66 100644
> --- a/src/fw/pciinit.c
> +++ b/src/fw/pciinit.c
> @@ -15,6 +15,7 @@
>   #include "hw/pcidevice.h" // pci_probe_devices
>   #include "hw/pci_ids.h" // PCI_VENDOR_ID_INTEL
>   #include "hw/pci_regs.h" // PCI_COMMAND
> +#include "fw/dev-pci.h" // qemu_pci_cap
>   #include "list.h" // struct hlist_node
>   #include "malloc.h" // free
>   #include "output.h" // dprintf
> @@ -578,9 +579,42 @@ pci_bios_init_bus_rec(int bus, u8 *pci_bus)
>           pci_bios_init_bus_rec(secbus, pci_bus);
>       if (subbus != *pci_bus) {
>        u8 res_bus = 0;
>        if (pci_config_readw(bdf, PCI_VENDOR_ID) == PCI_VENDOR_ID_REDHAT &&
>                pci_config_readw(bdf, PCI_DEVICE_ID) ==
>                        PCI_DEVICE_ID_REDHAT_ROOT_PORT) {

I think I already pointed out you should extract the code receiving
the limit into a different function. Also now you have a chance
to re-use the code for IO/MEM resources.
>            u8 cap;
>            do {
>                cap = pci_find_capability(bdf, PCI_CAP_ID_VNDR, 0);

Maybe I missed something, but how would the do-while will work
if you always use pci_find_capability with offset 0. It will
always start the search from 0 and find the same (first) capability,
right?
Maybe you need:
   cap = pci_find_capability(bdf, PCI_CAP_ID_VNDR, cap);
>            } while (cap &&
>                     pci_config_readb(bdf, cap + PCI_CAP_REDHAT_TYPE) !=
>                            REDHAT_CAP_TYPE_QEMU);
>            if (cap) {
>                u8 cap_len = pci_config_readb(bdf, cap + PCI_CAP_FLAGS);
>                if (cap_len != QEMU_PCI_CAP_SIZE) {
>                    dprintf(1, "PCI: QEMU cap length %d is invalid\n",
>                            cap_len);
>                } else {
>                    u32 tmp_res_bus = pci_config_readl(bdf,
>                                               cap + QEMU_PCI_CAP_BUS_RES);
>                    if (tmp_res_bus != (u32)-1) {

I would extract the above check into a separate function
to make code more readable

pci_qemu_res_cap_set(cap) { return cap != (u32)-1 }

then the code will look like:

if(pci_qemu_res_cap_set(res_bus)) {
>                        res_bus = tmp_res_bus & 0xFF;
>                        if ((u8)(res_bus + secbus) < secbus ||
>                            (u8)(res_bus + secbus) < res_bus) {
>                            dprintf(1, "PCI: bus_reserve value %d is invalid\n",
>                                    res_bus);
>                            res_bus = 0;
>                        }
>                    }
>                }
>            }
>            res_bus = (*pci_bus > secbus + res_bus) ? *pci_bus
>                                                  : secbus + res_bus;
>        }
>         dprintf(1, "PCI: subordinate bus = 0x%x -> 0x%x\n",
>                subbus, *pci_bus);
>        subbus = *pci_bus;
>                subbus, res_bus);
>        subbus = res_bus;
>        *pci_bus = res_bus;
>     } else {
>         dprintf(1, "PCI: subordinate bus = 0x%x\n", subbus);
>     }
>
> @@ -951,11 +985,38 @@ pci_region_map_one_entry(struct pci_region_entry *entry, u64 addr)
>   u16 bdf = entry->dev->bdf;
>   u64 limit = addr + entry->size - 1;
> if (pci_config_readw(bdf, PCI_VENDOR_ID) == PCI_VENDOR_ID_REDHAT &&
>        pci_config_readw(bdf, PCI_DEVICE_ID) ==
>                PCI_DEVICE_ID_REDHAT_ROOT_PORT) {
>    u8 cap;
>    do {
>        cap = pci_find_capability(bdf, PCI_CAP_ID_VNDR, 0);
>    } while (cap &&
>             pci_config_readb(bdf, cap + PCI_CAP_REDHAT_TYPE) !=
>                    REDHAT_CAP_TYPE_QEMU);
>    if (cap) {
>        u8 cap_len = pci_config_readb(bdf, cap + PCI_CAP_FLAGS);
>        if (cap_len != QEMU_PCI_CAP_SIZE) {
>            dprintf(1, "PCI: QEMU cap length %d is invalid\n",
>                    cap_len);

The above code should be re-used.
>        } else {
>            u32 offset = cap + QEMU_PCI_CAP_LIMITS_OFFSET + entry->type * 8;
>            u64 tmp_limit = (pci_config_readl(bdf, offset) |
>                        (u64)pci_config_readl(bdf, offset + 4) << 32);
>            if (tmp_limit != (u64)-1) {
>                tmp_limit += addr - 1;
>                limit = (limit > tmp_limit) ? limit : tmp_limit;
>            }

I think it is too late to read (and use) the cap value here,
because a lot of computations including IO/MEM ranges takes place 
earlier, see:
   pci_bios_check_devices

pci_bios_map_devices uses previously computed ranges, at this time
I think you shouldn't change ranges.
>        }
>    }
> }
> if (entry->type == PCI_REGION_TYPE_IO) {
>     pci_config_writeb(bdf, PCI_IO_BASE, addr >> PCI_IO_SHIFT);
>    pci_config_writew(bdf, PCI_IO_BASE_UPPER16, 0);
>    pci_config_writew(bdf, PCI_IO_BASE_UPPER16, limit >> 16);
>     pci_config_writeb(bdf, PCI_IO_LIMIT, limit >> PCI_IO_SHIFT);
>    pci_config_writew(bdf, PCI_IO_LIMIT_UPPER16, 0);
>    pci_config_writew(bdf, PCI_IO_LIMIT_UPPER16, limit >> 16);

Judging the above code, it seems SeaBIOS does not support 32-bit IO,
I am not sure yuo can change that.

Thanks,
Marcel
>   }
>   if (entry->type == PCI_REGION_TYPE_MEM) {
>       pci_config_writew(bdf, PCI_MEMORY_BASE, addr >> PCI_MEMORY_SHIFT);
>
> diff --git a/src/hw/pci_ids.h b/src/hw/pci_ids.h
> index 4ac73b4..38fa2ca 100644
> --- a/src/hw/pci_ids.h
> +++ b/src/hw/pci_ids.h
> @@ -2263,6 +2263,9 @@
>   #define PCI_DEVICE_ID_KORENIX_JETCARDF0	0x1600
>   #define PCI_DEVICE_ID_KORENIX_JETCARDF1	0x16ff
>
> +#define PCI_VENDOR_ID_REDHAT		0x1b36
> +#define PCI_DEVICE_ID_REDHAT_ROOT_PORT	0x000C
> #define PCI_VENDOR_ID_TEKRAM		0x1de1
> #define PCI_DEVICE_ID_TEKRAM_DC290	0xdc29

[PATCH v4 3/3] pci: enable RedHat PCI bridges to reserve additional buses on PCI init

[Michael S. Tsirkin]

On Sat, Aug 05, 2017 at 11:29:54PM +0300, Aleksandr Bezzubikov wrote:
> In case of Red Hat Generic PCIE Root Port reserve additional buses,
> which number is provided in a vendor-specific capability.
> Signed-off-by: Aleksandr Bezzubikov
>
> src/fw/pciinit.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++----
>  src/hw/pci_ids.h |  3 +++
>  2 files changed, 68 insertions(+), 4 deletions(-)
>
> diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
> index 864954f..d241d66 100644
> --- a/src/fw/pciinit.c
> +++ b/src/fw/pciinit.c
> @@ -15,6 +15,7 @@
>  #include "hw/pcidevice.h" // pci_probe_devices
>  #include "hw/pci_ids.h" // PCI_VENDOR_ID_INTEL
>  #include "hw/pci_regs.h" // PCI_COMMAND
> +#include "fw/dev-pci.h" // qemu_pci_cap
>  #include "list.h" // struct hlist_node
>  #include "malloc.h" // free
>  #include "output.h" // dprintf
> @@ -578,9 +579,42 @@ pci_bios_init_bus_rec(int bus, u8 *pci_bus)
>          pci_bios_init_bus_rec(secbus, pci_bus);
>      if (subbus != *pci_bus) {
>        u8 res_bus = 0;
>        if (pci_config_readw(bdf, PCI_VENDOR_ID) == PCI_VENDOR_ID_REDHAT &&
>                pci_config_readw(bdf, PCI_DEVICE_ID) ==
>                        PCI_DEVICE_ID_REDHAT_ROOT_PORT) {
>            u8 cap;
>            do {
>                cap = pci_find_capability(bdf, PCI_CAP_ID_VNDR, 0);
>            } while (cap &&
>                     pci_config_readb(bdf, cap + PCI_CAP_REDHAT_TYPE) !=
>                            REDHAT_CAP_TYPE_QEMU);
>            if (cap) {
>                u8 cap_len = pci_config_readb(bdf, cap + PCI_CAP_FLAGS);
>                if (cap_len != QEMU_PCI_CAP_SIZE) {
>                    dprintf(1, "PCI: QEMU cap length %d is invalid\n",
>                            cap_len);

I would do cap_len < QEMU_PCI_CAP_SIZE here - this way you can extend
the capability without breaking things.
>                } else {
>                    u32 tmp_res_bus = pci_config_readl(bdf,
>                                               cap + QEMU_PCI_CAP_BUS_RES);
>                    if (tmp_res_bus != (u32)-1) {
>                        res_bus = tmp_res_bus & 0xFF;
>                        if ((u8)(res_bus + secbus) < secbus ||
>                            (u8)(res_bus + secbus) < res_bus) {
>                            dprintf(1, "PCI: bus_reserve value %d is invalid\n",
>                                    res_bus);
>                            res_bus = 0;
>                        }
>                    }
>                }
>            }
>            res_bus = (*pci_bus > secbus + res_bus) ? *pci_bus
>                                                  : secbus + res_bus;
>        }
>        dprintf(1, "PCI: subordinate bus = 0x%x -> 0x%x\n",
>                subbus, *pci_bus);
>        subbus = *pci_bus;
>                subbus, res_bus);
>        subbus = res_bus;
>        *pci_bus = res_bus;
>    } else {
>        dprintf(1, "PCI: subordinate bus = 0x%x\n", subbus);
>    }
>
> @@ -951,11 +985,38 @@ pci_region_map_one_entry(struct pci_region_entry *entry, u64 addr)
>  u16 bdf = entry->dev->bdf;
>  u64 limit = addr + entry->size - 1;
> if (pci_config_readw(bdf, PCI_VENDOR_ID) == PCI_VENDOR_ID_REDHAT &&
>        pci_config_readw(bdf, PCI_DEVICE_ID) ==
>                PCI_DEVICE_ID_REDHAT_ROOT_PORT) {
>    u8 cap;
>    do {
>        cap = pci_find_capability(bdf, PCI_CAP_ID_VNDR, 0);
>    } while (cap &&
>             pci_config_readb(bdf, cap + PCI_CAP_REDHAT_TYPE) !=
>                    REDHAT_CAP_TYPE_QEMU);
>    if (cap) {
>        u8 cap_len = pci_config_readb(bdf, cap + PCI_CAP_FLAGS);
>        if (cap_len != QEMU_PCI_CAP_SIZE) {
>            dprintf(1, "PCI: QEMU cap length %d is invalid\n",
>                    cap_len);

Same here.
>        } else {
>            u32 offset = cap + QEMU_PCI_CAP_LIMITS_OFFSET + entry->type * 8;

what is this doing exactly? type is an enum so it's a trick. I'd rather
have an inline with a switch. Use it for bus as well.
>            u64 tmp_limit = (pci_config_readl(bdf, offset) |
>                        (u64)pci_config_readl(bdf, offset + 4) << 32);
>            if (tmp_limit != (u64)-1) {
>                tmp_limit += addr - 1;
>                limit = (limit > tmp_limit) ? limit : tmp_limit;
>            }
>        }
>    }
> }
> if (entry->type == PCI_REGION_TYPE_IO) {
>        pci_config_writeb(bdf, PCI_IO_BASE, addr >> PCI_IO_SHIFT);
>    pci_config_writew(bdf, PCI_IO_BASE_UPPER16, 0);
>    pci_config_writew(bdf, PCI_IO_BASE_UPPER16, limit >> 16);
>    pci_config_writeb(bdf, PCI_IO_LIMIT, limit >> PCI_IO_SHIFT);
>    pci_config_writew(bdf, PCI_IO_LIMIT_UPPER16, 0);
>    pci_config_writew(bdf, PCI_IO_LIMIT_UPPER16, limit >> 16);
> }
>    if (entry->type == PCI_REGION_TYPE_MEM) {
>        pci_config_writew(bdf, PCI_MEMORY_BASE, addr >> PCI_MEMORY_SHIFT);
>
> diff --git a/src/hw/pci_ids.h b/src/hw/pci_ids.h
> index 4ac73b4..38fa2ca 100644
> --- a/src/hw/pci_ids.h
> +++ b/src/hw/pci_ids.h
> @@ -2263,6 +2263,9 @@
>  #define PCI_DEVICE_ID_KORENIX_JETCARDF0	0x1600
>  #define PCI_DEVICE_ID_KORENIX_JETCARDF1	0x16ff
>
> +#define PCI_VENDOR_ID_REDHAT		0x1b36
> +#define PCI_DEVICE_ID_REDHAT_ROOT_PORT	0x000C
>
> #define PCI_VENDOR_ID_TEKRAM		0x1de1
>  #define PCI_DEVICE_ID_TEKRAM_DC290	0xdc29