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Re: [PATCH RESEND] pci: Disallow improper BAR registration for type 1
From: |
Ben Widawsky |
Subject: |
Re: [PATCH RESEND] pci: Disallow improper BAR registration for type 1 |
Date: |
Wed, 14 Oct 2020 10:56:51 -0700 |
On 20-10-14 13:52:29, Michael S. Tsirkin wrote:
> On Wed, Oct 14, 2020 at 10:18:53AM -0700, Ben Widawsky wrote:
> > This patch informs future developers working on root complexes, root
> > ports, or bridges that also wish to implement a BAR for those. PCI type
> > 1 headers only support 2 base address registers. It is incorrect and
> > difficult to figure out what is wrong with the device when this mistake
> > is made. With this, it is immediate and obvious what has gone wrong.
> >
> > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
>
> How about an assert + a comment?
> This is how we usually handle developer bugs. error_report is
> for user errors and similar issues ...
Sure, I can do that. I was copying the error above mine which should probably
also be changed to an assert then, yes?
I can submit that as well with v2 of this if you'd like.
>
> > ---
> > hw/pci/pci.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> > diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> > index 3c8f10b461..55b0302c57 100644
> > --- a/hw/pci/pci.c
> > +++ b/hw/pci/pci.c
> > @@ -1141,6 +1141,7 @@ void pci_register_bar(PCIDevice *pci_dev, int
> > region_num,
> > uint32_t addr; /* offset in pci config space */
> > uint64_t wmask;
> > pcibus_t size = memory_region_size(memory);
> > + uint8_t hdr_type;
> >
> > assert(region_num >= 0);
> > assert(region_num < PCI_NUM_REGIONS);
> > @@ -1150,6 +1151,15 @@ void pci_register_bar(PCIDevice *pci_dev, int
> > region_num,
> > exit(1);
> > }
> >
> > + hdr_type =
> > + pci_dev->config[PCI_HEADER_TYPE] & ~PCI_HEADER_TYPE_MULTI_FUNCTION;
> > + if (hdr_type == PCI_HEADER_TYPE_BRIDGE && region_num > 1) {
> > + error_report("ERROR: PCI Type 1 header only has 2 BARs "
> > + "requested BAR=%d",
> > + region_num);
> > + exit(1);
> > + }
> > +
> > r = &pci_dev->io_regions[region_num];
> > r->addr = PCI_BAR_UNMAPPED;
> > r->size = size;
> > --
> > 2.28.0
>