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Re: [PATCH RESEND] pci: Disallow improper BAR registration for type 1
From: |
Michael S. Tsirkin |
Subject: |
Re: [PATCH RESEND] pci: Disallow improper BAR registration for type 1 |
Date: |
Wed, 14 Oct 2020 13:52:29 -0400 |
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 ...
> ---
> 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