.../BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
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.roth@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;
RmpPageSize = Info->Entry[StartIndex].PageSize;
Ret = AsmPvalidate (RmpPageSize, Validate, Address);
--
2.25.1
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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.roth@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 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#111137): https://edk2.groups.io/g/devel/message/111137 Mute This Topic: https://groups.io/mt/102520474/1787277 Group Owner: devel+owner@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [importer@patchew.org] -=-=-=-=-=-=-=-=-=-=-=-
Quoting Gerd Hoffmann (2023-11-13 04:48:10) > 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.roth@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? My original thinking was that we were originally shifting a 40-bit bit-field of a UINT64, so the minimal change is to cast it to a normal UINT64 to fix the bit-field overflow. So I thought casting to another type might obfuscate the fix a bit. EFI_PHYSICAL_ADDRESS seems more correct all around though, so I've sent a v2 with the suggested change. Thanks! -Mike > > Otherwise looks good to me. > > take care, > Gerd > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#111284): https://edk2.groups.io/g/devel/message/111284 Mute This Topic: https://groups.io/mt/102520474/1787277 Group Owner: devel+owner@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [importer@patchew.org] -=-=-=-=-=-=-=-=-=-=-=-
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