Re: [PATCH v2 kvmtool 20/30] pci: Add helpers for BAR values and memory/IO space access

[Andre Przywara <andre.przywara@arm.com>]

On Thu, 23 Jan 2020 13:47:55 +0000
Alexandru Elisei <alexandru.elisei@arm.com> wrote:

Hi,

> We're going to be checking the BAR type, the address written to it and
> if access to memory or I/O space is enabled quite often when we add
> support for reasignable BARs, add helpers for it.

I am not a particular fan of these double underscores inside identifiers, but I guess that is too late now, since it's already all over the place. So:

> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>

Reviewed-by: Andre Przywara <andre.przywara@arm.com>

Cheers,
Andre.

> ---
>  include/kvm/pci.h | 48 +++++++++++++++++++++++++++++++++++++++++++++++
>  pci.c             |  2 +-
>  2 files changed, 49 insertions(+), 1 deletion(-)
> 
> diff --git a/include/kvm/pci.h b/include/kvm/pci.h
> index ccb155e3e8fe..235cd82fff3c 100644
> --- a/include/kvm/pci.h
> +++ b/include/kvm/pci.h
> @@ -5,6 +5,7 @@
>  #include <linux/kvm.h>
>  #include <linux/pci_regs.h>
>  #include <endian.h>
> +#include <stdbool.h>
>  
>  #include "kvm/devices.h"
>  #include "kvm/msi.h"
> @@ -161,4 +162,51 @@ void pci__config_rd(struct kvm *kvm, union pci_config_address addr, void *data,
>  
>  void *pci_find_cap(struct pci_device_header *hdr, u8 cap_type);
>  
> +static inline bool __pci__memory_space_enabled(u16 command)
> +{
> +	return command & PCI_COMMAND_MEMORY;
> +}
> +
> +static inline bool pci__memory_space_enabled(struct pci_device_header *pci_hdr)
> +{
> +	return __pci__memory_space_enabled(pci_hdr->command);
> +}
> +
> +static inline bool __pci__io_space_enabled(u16 command)
> +{
> +	return command & PCI_COMMAND_IO;
> +}
> +
> +static inline bool pci__io_space_enabled(struct pci_device_header *pci_hdr)
> +{
> +	return __pci__io_space_enabled(pci_hdr->command);
> +}
> +
> +static inline bool __pci__bar_is_io(u32 bar)
> +{
> +	return bar & PCI_BASE_ADDRESS_SPACE_IO;
> +}
> +
> +static inline bool pci__bar_is_io(struct pci_device_header *pci_hdr, int bar_num)
> +{
> +	return __pci__bar_is_io(pci_hdr->bar[bar_num]);
> +}
> +
> +static inline bool pci__bar_is_memory(struct pci_device_header *pci_hdr, int bar_num)
> +{
> +	return !pci__bar_is_io(pci_hdr, bar_num);
> +}
> +
> +static inline u32 __pci__bar_address(u32 bar)
> +{
> +	if (__pci__bar_is_io(bar))
> +		return bar & PCI_BASE_ADDRESS_IO_MASK;
> +	return bar & PCI_BASE_ADDRESS_MEM_MASK;
> +}
> +
> +static inline u32 pci__bar_address(struct pci_device_header *pci_hdr, int bar_num)
> +{
> +	return __pci__bar_address(pci_hdr->bar[bar_num]);
> +}
> +
>  #endif /* KVM__PCI_H */
> diff --git a/pci.c b/pci.c
> index b6892d974c08..4f7b863298f6 100644
> --- a/pci.c
> +++ b/pci.c
> @@ -185,7 +185,7 @@ void pci__config_wr(struct kvm *kvm, union pci_config_address addr, void *data,
>  	 * size, it will write the address back.
>  	 */
>  	if (bar < 6) {
> -		if (pci_hdr->bar[bar] & PCI_BASE_ADDRESS_SPACE_IO)
> +		if (pci__bar_is_io(pci_hdr, bar))
>  			mask = (u32)PCI_BASE_ADDRESS_IO_MASK;
>  		else
>  			mask = (u32)PCI_BASE_ADDRESS_MEM_MASK;