[SeaBIOS] Re: [PATCH 1/4] pci: Allow scanning pci bus number up to 255 in CSM mode

[Paul Menzel]

Dear Bin,


Thank you very much for your patches.

Am 01.01.21 um 04:08 schrieb Bin Gao:

On real hardware especially server platforms, there might be multiple


Please give a concrete example of the hardware.


root buses, thus pci bus number could run up to 255. This patch fixed


Nit: I’d use present tense in commit messages: This patch fixes ….


pci_probe_devices() by allowing to scan all 256 pci bus numbers(0-255).


Nit: Space before (.


Signed-off-by: Bin Gao 
---
  src/hw/pcidevice.c | 8 
  1 file changed, 8 insertions(+)

diff --git a/src/hw/pcidevice.c b/src/hw/pcidevice.c
index 8853cf7..8d9c401 100644
--- a/src/hw/pcidevice.c
+++ b/src/hw/pcidevice.c
@@ -26,6 +26,14 @@ pci_probe_devices(void)
  struct hlist_node **pprev = 
  int extraroots = romfile_loadint("etc/extra-pci-roots", 0);
  int bus = -1, lastbus = 0, rootbuses = 0, count=0;
+
+// There might be multiple PCI root buses on physical hardware especially
+// server platforms, thus bus number could run up to the top value,
+// i.e. 0xff. Setting extraroots to 0xff to ensure we can enumerate all
+// PCI bus numbers.
+if (CONFIG_CSM)
+extraroots = 0xff;
+


Can there be a romfile with CSM? If yes, the configured value would be 
overwritten. Maybe add a log message in that case?



  while (bus < 0xff && (bus < MaxPCIBus || rootbuses < extraroots)) {
  bus++;
  int bdf;




Kind regards,

Paul
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[SeaBIOS] Re: [PATCH 3/4] csm: Move pci_probe_devices() from InitializeYourself phase to PreparToBoot phase

[Paul Menzel]

Dear Bin,


Thank you for your patches.

Am 01.01.21 um 04:08 schrieb Bin Gao:

On physical hardware, some PCI devices are not detectable when
UEFI invokes our InitializeYourself() function.


It would be great, if you gave a concrete example of hardware (board, 
firmware version and PCI devices).



But they are guaranteed to be available before UEFI invokes our
PreparToBoot() function.


Nit: Small typo (also in summary and comment below): Prepar*e*ToBoot.


Signed-off-by: Bin Gao 
---
  src/fw/csm.c | 11 ++-
  1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/fw/csm.c b/src/fw/csm.c
index f64bc73..1bd821e 100644
--- a/src/fw/csm.c
+++ b/src/fw/csm.c
@@ -64,7 +64,9 @@ static void
  csm_maininit(struct bregs *regs)
  {
  interface_init();
-pci_probe_devices();
+
+if (CONFIG_CSM && CONFIG_QEMU_HARDWARE)
+pci_probe_devices();
  
  csm_compat_table.PnPInstallationCheckSegment = SEG_BIOS;

  csm_compat_table.PnPInstallationCheckOffset = get_pnp_offset();
@@ -144,6 +146,13 @@ handle_csm_0002(struct bregs *regs)
  return;
  }
  
+// On physical hardware, some PCI devices are not detectable when

+// UEFI invokes our InitializeYourself() function. But they
+// are guaranteed to be available before UEFI invokes our
+// PreparToBoot() function.
+if (CONFIG_CSM && !CONFIG_QEMU_HARDWARE)
+pci_probe_devices();
+
  dprintf(3, "PrepareToBoot table %04x:%04x\n", regs->es, regs->bx);
  
  struct e820entry *p = (void *)csm_compat_table.E820Pointer;


Why don’t we want to do the same for QEMU?


Kind regards,

Paul
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