[edk2-devel] [PATCH V4 27/31] OvmfPkg: Update IoMmuDxe to support TDX

[Gerd Hoffmann]

On Mon, Dec 13, 2021 at 08:56:58PM +0800, Min Xu wrote:
> RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429
> 
> The IOMMU protocol driver provides capabilities to set a DMA access
> attribute and methods to allocate, free, map and unmap the DMA memory
> for the PCI Bus devices.
> 
> The current IoMmuDxe driver supports DMA operations inside SEV guest.
> To support DMA operation in TDX guest,
> CC_GUEST_IS_XXX (PcdConfidentialComputingGuestAttr) is used to determine
> if it is SEV guest or TDX guest.
> 
> Due to security reasons all DMA operations inside the SEV/TDX guest must
> be performed on shared pages. The IOMMU protocol driver for the SEV/TDX
> guest uses a bounce buffer to map guest DMA buffer to shared pages in
> order to provide the support for DMA operations inside SEV/TDX guest.
> 
> The call of SEV or TDX specific function to set/clear EncMask/SharedBit
> is determined by CC_GUEST_IS_XXX (PcdConfidentialComputingGuestAttr).
> 
> Cc: Ard Biesheuvel <ardb+tianocore at kernel.org>
> Cc: Jordan Justen <jordan.l.justen at intel.com>
> Cc: Brijesh Singh <brijesh.singh at amd.com>
> Cc: Erdem Aktas <erdemaktas at google.com>
> Cc: James Bottomley <jejb at linux.ibm.com>
> Cc: Jiewen Yao <jiewen.yao at intel.com>
> Cc: Tom Lendacky <thomas.lendacky at amd.com>
> Cc: Gerd Hoffmann <kraxel at redhat.com>
> Signed-off-by: Min Xu <min.m.xu at intel.com>

Acked-by: Gerd Hoffmann <kraxel at redhat.com>



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