comments below: On 05/22/17 17:23, Brijesh Singh wrote: > When SEV is enabled, use a bounce buffer to perform the DMA operation. > > > Cc: Jordan Justen <[email protected]> > Cc: Laszlo Ersek <[email protected]> > Contributed-under: TianoCore Contribution Agreement 1.0 > Signed-off-by: Brijesh Singh <[email protected]> > --- > OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c | 54 +++++++++++++++++++- > 1 file changed, 52 insertions(+), 2 deletions(-) > > diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c > b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c > index 73a19772bee1..40b43ac78ff4 100644 > --- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c > +++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c > @@ -72,6 +72,8 @@ InternalQemuFwCfgDmaBytes ( > volatile FW_CFG_DMA_ACCESS *Access; > UINT32 AccessHigh, AccessLow; > UINT32 Status; > + UINT32 NumPages; > + VOID *DmaBuffer, *BounceBuffer; > > ASSERT (Control == FW_CFG_DMA_CTL_WRITE || Control == FW_CFG_DMA_CTL_READ > || > Control == FW_CFG_DMA_CTL_SKIP); > @@ -80,11 +82,44 @@ InternalQemuFwCfgDmaBytes ( > return; > } > > - Access = &LocalAccess; > + // > + // When SEV is enabled then allocate DMA bounce buffer > + // > + if (InternalQemuFwCfgSevIsEnabled ()) { > + UINTN TotalSize; > + > + TotalSize = sizeof (*Access); > + // > + // Control operation does not need buffer > + //
(1) you missed my remark that this comment should say "skip operation", see point (2) in <[email protected]">http://mid.mail-archive.com/[email protected]>. > + if (Control != FW_CFG_DMA_CTL_SKIP) { > + TotalSize += Size; > + } > + > + // > + // Allocate SEV DMA buffer > + // > + NumPages = (UINT32)EFI_SIZE_TO_PAGES (TotalSize); > + InternalQemuFwCfgSevDmaAllocateBuffer (&BounceBuffer, NumPages); > + > + Access = BounceBuffer; > + DmaBuffer = (UINT8*)BounceBuffer + sizeof (*Access); > + > + // > + // Decrypt data from encrypted guest buffer into DMA buffer > + // > + if (Control == FW_CFG_DMA_CTL_WRITE) { > + CopyMem (DmaBuffer, Buffer, Size); > + } > + } else { > + Access = &LocalAccess; > + DmaBuffer = Buffer; > + BounceBuffer = NULL; > + } > > Access->Control = SwapBytes32 (Control); > Access->Length = SwapBytes32 (Size); > - Access->Address = SwapBytes64 ((UINTN)Buffer); > + Access->Address = SwapBytes64 ((UINTN)DmaBuffer); > > // > // Delimit the transfer from (a) modifications to Access, (b) in case of a > @@ -117,6 +152,21 @@ InternalQemuFwCfgDmaBytes ( > // After a read, the caller will want to use Buffer. > // > MemoryFence (); > + > + // > + // If Bounce buffer was allocated then copy the data into guest buffer and > + // free the bounce buffer > + // > + if (BounceBuffer) { (2) You missed my remark about the edk2 coding style, see point (6) in <https://www.mail-archive.com/[email protected]/msg25650.html>. > + // > + // Encrypt the data from DMA buffer into guest buffer > + // > + if (Control == FW_CFG_DMA_CTL_READ) { > + CopyMem (Buffer, DmaBuffer, Size); > + } > + > + InternalQemuFwCfgSevDmaFreeBuffer (BounceBuffer, NumPages); > + } > } > > > If a v6 is necessary, then please fix up the above. Otherwise, the patch is good to me as-is. Reviewed-by: Laszlo Ersek <[email protected]> Thanks Laszlo _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
