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MdePkg/BaseLib: Add a new VMGEXIT instruction invocation for SVSM

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BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4654

The SVSM specification relies on a specific register calling convention to
hold the parameters that are associated with the SVSM request. The SVSM is
invoked by requesting the hypervisor to run the VMPL0 VMSA of the guest
using the GHCB MSR Protocol or a GHCB NAE event.

Create a new version of the VMGEXIT instruction that will adhere to this
calling convention and load the SVSM function arguments into the proper
register before invoking the VMGEXIT instruction. On return, perform the
atomic exchange on the SVSM call pending value as specified in the SVSM
specification.

Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
This commit is contained in:
Tom Lendacky
2024-03-08 07:31:25 -08:00
committed by mergify[bot]
parent 8ccbf075f0
commit c0bf953fe8
4 changed files with 174 additions and 0 deletions
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39
MdePkg/Include/Library/BaseLib.h
View File

@@ -7876,6 +7876,45 @@ AsmVmgExit (
VOID
);
///
/// The structure used to supply and return data to and from the SVSM.
///
typedef struct {
VOID *Caa;
UINT64 RaxIn;
UINT64 RcxIn;
UINT64 RdxIn;
UINT64 R8In;
UINT64 R9In;
UINT64 RaxOut;
UINT64 RcxOut;
UINT64 RdxOut;
UINT64 R8Out;
UINT64 R9Out;
UINT8 *CallPending;
} SVSM_CALL_DATA;
/**
Executes a VMGEXIT instruction (VMMCALL with a REP prefix) with arguments
and return code
Executes a VMGEXIT instruction placing the specified arguments in the
corresponding registers before invocation. Upon return an XCHG is done to
atomically clear and retrieve the SVSM call pending value. The returned RAX
register value becomes the function return code. This function is intended
for use with an SVSM. This function is only available on IA-32 and x64.
@param[in,out] SvsmCallPending Pointer to the location of the SVSM call data
@return Value of the RAX register on return
**/
UINT32
EFIAPI
AsmVmgExitSvsm (
IN OUT SVSM_CALL_DATA *SvsmCallData
);
/**
Patch the immediate operand of an IA32 or X64 instruction such that the byte,
word, dword or qword operand is encoded at the end of the instruction's