On Fri, Nov 10, 2023 at 08:14:39PM -0600, Michael Roth wrote:
> The struct used for GHCB-based page-state change requests uses a 40-bit
> bit-field for the GFN, which is shifted by PAGE_SHIFT to generate a
> 64-bit address. However, anything beyond 40-bits simply gets shifted off
> when doing this, which will cause issues when dealing with 1TB+
> addresses. Fix this by casting the 40-bit GFN values to 64-bit ones
> prior to shifting it by PAGE_SHIFT.
>
> Fixes: ade62c18f474 ("OvmfPkg/MemEncryptSevLib: add support to validate
> system RAM")
> Signed-off-by: Michael Roth <michael.r...@amd.com>
> ---
> .../BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git
> a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
> b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
> index 85eb41585b..d52d2940e9 100644
> --- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
> +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
> @@ -78,13 +78,14 @@ PvalidateRange (
> IN BOOLEAN Validate
> )
> {
> - UINTN Address, RmpPageSize, Ret, i;
> + UINTN RmpPageSize, Ret, i;
> + EFI_PHYSICAL_ADDRESS Address;
>
> for ( ; StartIndex <= EndIndex; StartIndex++) {
> //
> // Get the address and the page size from the Info.
> //
> - Address = Info->Entry[StartIndex].GuestFrameNumber << EFI_PAGE_SHIFT;
> + Address = ((UINT64)Info->Entry[StartIndex].GuestFrameNumber) <<
> EFI_PAGE_SHIFT;
Minor nit: why cast to UINT64 not EFI_PHYSICAL_ADDRESS?
Otherwise looks good to me.
take care,
Gerd
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