On Thu, Jul 28, 2011 at 12:01 PM, Sasha Levin <levinsasha928@xxxxxxxxx> wrote:
> PCI BAR probing is done in four steps:
>
> 1. Read address (and flags).
> 2. Mask BAR.
> 3. Read BAR again - Now the expected result is the size of the BAR.
> 4. Mask BAR with address.
>
> So far, we have only took care of the first step. This means that the kernel
> was using address as the size, causing a PCI allocation blunder.
>
> This patch fixes the issue by passing a proper size after masking.
>
> Signed-off-by: Sasha Levin <levinsasha928@xxxxxxxxx>
> ---
> tools/kvm/include/kvm/pci.h | 1 +
> tools/kvm/pci.c | 57 +++++++++++++++++++++++++++++++++++++++----
> 2 files changed, 53 insertions(+), 5 deletions(-)
>
> diff --git a/tools/kvm/include/kvm/pci.h b/tools/kvm/include/kvm/pci.h
> index 6ad4426..a7532e3 100644
> --- a/tools/kvm/include/kvm/pci.h
> +++ b/tools/kvm/include/kvm/pci.h
> @@ -51,5 +51,6 @@ struct pci_device_header {
>
> void pci__init(void);
> void pci__register(struct pci_device_header *dev, u8 dev_num);
> +u32 pci_get_io_space_block(void);
s/pci_get_io_space_block/pci__get_io_space_block/
>
> #endif /* KVM__PCI_H */
> diff --git a/tools/kvm/pci.c b/tools/kvm/pci.c
> index a1ad8ba..799536e3 100644
> --- a/tools/kvm/pci.c
> +++ b/tools/kvm/pci.c
> @@ -5,11 +5,23 @@
> #include <assert.h>
>
> #define PCI_MAX_DEVICES 256
> +#define PCI_IO_SIZE 0x100
>
> static struct pci_device_header *pci_devices[PCI_MAX_DEVICES];
>
> static struct pci_config_address pci_config_address;
>
> +/* This is within our PCI gap */
> +static u32 io_space_blocks = 0xE1000000;
The magic number wants to be a constant. Preferably somewhere near
where we specify the PCI gap in.
> +
> +u32 pci_get_io_space_block(void)
> +{
> + u32 block = io_space_blocks;
> + io_space_blocks += PCI_IO_SIZE;
> +
> + return block;
> +}
> +
> static void *pci_config_address_ptr(u16 port)
> {
> unsigned long offset;
> @@ -44,11 +56,6 @@ static struct ioport_operations pci_config_address_ops = {
> .io_out = pci_config_address_out,
> };
>
> -static bool pci_config_data_out(struct ioport *ioport, struct kvm *kvm, u16 port, void *data, int size, u32 count)
> -{
> - return true;
> -}
> -
> static bool pci_device_exists(u8 bus_number, u8 device_number, u8 function_number)
> {
> struct pci_device_header *dev;
> @@ -67,6 +74,46 @@ static bool pci_device_exists(u8 bus_number, u8 device_number, u8 function_numbe
> return dev != NULL;
> }
>
> +static bool pci_config_data_out(struct ioport *ioport, struct kvm *kvm, u16 port, void *data, int size, u32 count)
> +{
> + unsigned long start;
> + u8 dev_num;
> +
> + /*
> + * If someone accesses PCI configuration space offsets that are not
> + * aligned to 4 bytes, it uses ioports to signify that.
> + */
> + start = port - PCI_CONFIG_DATA;
> +
> + dev_num = pci_config_address.device_number;
> +
> + if (pci_device_exists(0, dev_num, 0)) {
> + unsigned long offset;
> +
> + offset = start + (pci_config_address.register_number << 2);
> + if (offset < sizeof(struct pci_device_header)) {
> + void *p = pci_devices[dev_num];
> + u32 sz = PCI_IO_SIZE;
> +
> + /*
> + * If the kernel masks the BAR it would expect to find the
> + * size of the BAR there next time it reads from it.
> + * When the kernel got the size it would write the address
> + * back.
> + */
> + if ((offset >= offsetof(struct pci_device_header, bar[0])) &&
> + (offset <= offsetof(struct pci_device_header, bar[6]))) {
Maybe add a helper for the bar offset checks?
> + if (*(u32 *)(p + offset))
> + memcpy(p + offset, &sz, sizeof(sz));
> + } else if (*(u32 *)(p + offset)) {
> + memcpy(p + offset, data, size);
> + }
That if-else maze is pretty scary and needs to be simplified.
> + }
> + }
> +
> + return true;
> +}
> +
> static bool pci_config_data_in(struct ioport *ioport, struct kvm *kvm, u16 port, void *data, int size, u32 count)
> {
> unsigned long start;
> --
> 1.7.6
>
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