OvmfPkg/XenHypercallLib: Use direct hypercalls

This removes the need to allocate memory for the hypercall page,
particularly for use during runtime.  This also makes the library usable
in all phases, so LIBRARY_CLASS can remove the restrictions.

The processor vendor is used to select vmmcall or vmcall instructions.
The listed vendors are those in the Xen tree.

Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>

4 files changed, 148 insertions, 44 deletions

diff --git a/OvmfPkg/Library/XenHypercallLib/Ia32/hypercall.nasm b/OvmfPkg/Library/XenHypercallLib/Ia32/hypercall.nasm
index e0fa71bb5b..abcfcb55ce 100644
--- a/OvmfPkg/Library/XenHypercallLib/Ia32/hypercall.nasm
+++ b/OvmfPkg/Library/XenHypercallLib/Ia32/hypercall.nasm
@@ -2,24 +2,47 @@ SECTION .text
 

 ; INTN

 ; EFIAPI

-; __XenHypercall2 (

-;   IN     VOID *HypercallAddr,

+; __XenVmmcall2 (

+;   IN     INTN HypercallNum,

 ;   IN OUT INTN Arg1,

 ;   IN OUT INTN Arg2

 ;   );

-global ASM_PFX(__XenHypercall2)

-ASM_PFX(__XenHypercall2):

+global ASM_PFX(__XenVmmcall2)

+ASM_PFX(__XenVmmcall2):

   ; Save only ebx, ecx is supposed to be a scratch register and needs to be

   ; saved by the caller

   push ebx

-  ; Copy HypercallAddr to eax

+  ; Copy HypercallNum to eax

   mov eax, [esp + 8]

   ; Copy Arg1 to the register expected by Xen

   mov ebx, [esp + 12]

   ; Copy Arg2 to the register expected by Xen

   mov ecx, [esp + 16]

-  ; Call HypercallAddr

-  call eax

+  ; Call Hypercall

+  vmmcall

+  pop ebx

+  ret

+

+; INTN

+; EFIAPI

+; __XenVmcall2 (

+;   IN     INTN HypercallNum,

+;   IN OUT INTN Arg1,

+;   IN OUT INTN Arg2

+;   );

+global ASM_PFX(__XenVmcall2)

+ASM_PFX(__XenVmcall2):

+  ; Save only ebx, ecx is supposed to be a scratch register and needs to be

+  ; saved by the caller

+  push ebx

+  ; Copy HypercallNum to eax

+  mov eax, [esp + 8]

+  ; Copy Arg1 to the register expected by Xen

+  mov ebx, [esp + 12]

+  ; Copy Arg2 to the register expected by Xen

+  mov ecx, [esp + 16]

+  ; Call Hypercall

+  vmcall

   pop ebx

   ret

 

diff --git a/OvmfPkg/Library/XenHypercallLib/X64/hypercall.nasm b/OvmfPkg/Library/XenHypercallLib/X64/hypercall.nasm
index 5e6a0c05c5..469ac212f1 100644
--- a/OvmfPkg/Library/XenHypercallLib/X64/hypercall.nasm
+++ b/OvmfPkg/Library/XenHypercallLib/X64/hypercall.nasm
@@ -3,23 +3,46 @@ SECTION .text
 

 ; INTN

 ; EFIAPI

-; __XenHypercall2 (

-;   IN     VOID *HypercallAddr,

+; __XenVmmcall2 (

+;   IN     INTN HypercallNum,

 ;   IN OUT INTN Arg1,

 ;   IN OUT INTN Arg2

 ;   );

-global ASM_PFX(__XenHypercall2)

-ASM_PFX(__XenHypercall2):

+global ASM_PFX(__XenVmmcall2)

+ASM_PFX(__XenVmmcall2):

   push rdi

   push rsi

-  ; Copy HypercallAddr to rax

+  ; Copy HypercallNum to rax

   mov rax, rcx

   ; Copy Arg1 to the register expected by Xen

   mov rdi, rdx

   ; Copy Arg2 to the register expected by Xen

   mov rsi, r8

-  ; Call HypercallAddr

-  call rax

+  ; Call HypercallNum

+  vmmcall

+  pop rsi

+  pop rdi

+  ret

+

+; INTN

+; EFIAPI

+; __XenVmcall2 (

+;   IN     INTN HypercallNum,

+;   IN OUT INTN Arg1,

+;   IN OUT INTN Arg2

+;   );

+global ASM_PFX(__XenVmcall2)

+ASM_PFX(__XenVmcall2):

+  push rdi

+  push rsi

+  ; Copy HypercallNum to rax

+  mov rax, rcx

+  ; Copy Arg1 to the register expected by Xen

+  mov rdi, rdx

+  ; Copy Arg2 to the register expected by Xen

+  mov rsi, r8

+  ; Call HypercallNum

+  vmcall

   pop rsi

   pop rdi

   ret

diff --git a/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c b/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
index dcc6575250..a07d9e4d46 100644
--- a/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
+++ b/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
@@ -7,11 +7,31 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 **/

 

 #include <PiDxe.h>

-#include <Library/HobLib.h>

+#include <Library/BaseLib.h>

 #include <Library/DebugLib.h>

-#include <Guid/XenInfo.h>

+#include <Library/CpuLib.h>

 

-STATIC VOID  *HyperPage;

+static INTN     mUseVmmCall = -1;

+static BOOLEAN  mHypercallAvail;

+

+//

+// Interface exposed by the ASM implementation of the core hypercall

+//

+INTN

+EFIAPI

+__XenVmmcall2 (

+  IN     INTN  HypercallNum,

+  IN OUT INTN  Arg1,

+  IN OUT INTN  Arg2

+  );

+

+INTN

+EFIAPI

+__XenVmcall2 (

+  IN     INTN  HypercallNum,

+  IN OUT INTN  Arg1,

+  IN OUT INTN  Arg2

+  );

 

 /**

   Check if the Xen Hypercall library is able to make calls to the Xen

@@ -29,23 +49,38 @@ XenHypercallIsAvailable (
   VOID

   )

 {

-  return HyperPage != NULL;

+  return mHypercallAvail;

 }

 

-//

-// Interface exposed by the ASM implementation of the core hypercall

-//

-INTN

-EFIAPI

-__XenHypercall2 (

-  IN     VOID  *HypercallAddr,

-  IN OUT INTN  Arg1,

-  IN OUT INTN  Arg2

-  );

+STATIC

+UINT32

+XenCpuidLeaf (

+  VOID

+  )

+{

+  UINT8   Signature[13];

+  UINT32  XenLeaf;

+

+  Signature[12] = '\0';

+  for (XenLeaf = 0x40000000; XenLeaf < 0x40010000; XenLeaf += 0x100) {

+    AsmCpuid (

+      XenLeaf,

+      NULL,

+      (UINT32 *)&Signature[0],

+      (UINT32 *)&Signature[4],

+      (UINT32 *)&Signature[8]

+      );

+

+    if (!AsciiStrCmp ((CHAR8 *)Signature, "XenVMMXenVMM")) {

+      return XenLeaf;

+    }

+  }

+

+  return 0;

+}

 

 /**

-  Library constructor: retrieves the Hyperpage address

-  from the gEfiXenInfoGuid HOB

+  Library constructor: Check for Xen leaf in CPUID

 **/

 RETURN_STATUS

 EFIAPI

@@ -53,16 +88,41 @@ XenHypercallLibInit (
   VOID

   )

 {

-  EFI_HOB_GUID_TYPE  *GuidHob;

-  EFI_XEN_INFO       *XenInfo;

+  UINT32  XenLeaf;

+  CHAR8   sig[13];

 

-  GuidHob = GetFirstGuidHob (&gEfiXenInfoGuid);

-  if (GuidHob == NULL) {

+  XenLeaf = XenCpuidLeaf ();

+  if (XenLeaf == 0) {

     return RETURN_NOT_FOUND;

   }

 

-  XenInfo   = (EFI_XEN_INFO *)GET_GUID_HOB_DATA (GuidHob);

-  HyperPage = XenInfo->HyperPages;

+  sig[12] = '\0';

+  AsmCpuid (

+    0,

+    NULL,

+    (UINT32 *)&sig[0],

+    (UINT32 *)&sig[8],

+    (UINT32 *)&sig[4]

+    );

+

+  DEBUG ((DEBUG_INFO, "Detected CPU \"%12a\"\n", sig));

+

+  if ((AsciiStrCmp ("AuthenticAMD", sig) == 0) ||

+      (AsciiStrCmp ("HygonGenuine", sig) == 0))

+  {

+    mUseVmmCall = TRUE;

+  } else if ((AsciiStrCmp ("GenuineIntel", sig) == 0) ||

+             (AsciiStrCmp ("CentaurHauls", sig) == 0) ||

+             (AsciiStrCmp ("  Shanghai  ", sig) == 0))

+  {

+    mUseVmmCall = FALSE;

+  } else {

+    DEBUG ((DEBUG_ERROR, "Unsupported CPU vendor\n"));

+    return RETURN_NOT_FOUND;

+  }

+

+  mHypercallAvail = TRUE;

+

   return RETURN_SUCCESS;

 }

 

@@ -84,7 +144,9 @@ XenHypercall2 (
   IN OUT INTN   Arg2

   )

 {

-  ASSERT (HyperPage != NULL);

-

-  return __XenHypercall2 ((UINT8 *)HyperPage + HypercallID * 32, Arg1, Arg2);

+  if (mUseVmmCall) {

+    return __XenVmmcall2 (HypercallID, Arg1, Arg2);

+  } else {

+    return __XenVmcall2 (HypercallID, Arg1, Arg2);

+  }

 }

diff --git a/OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf b/OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf
index edb7787239..2321b61bf8 100644
--- a/OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf
+++ b/OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf
@@ -13,11 +13,6 @@
   MODULE_TYPE                    = BASE

   VERSION_STRING                 = 1.0

   CONSTRUCTOR                    = XenHypercallLibConstruct

-

-[Defines.IA32, Defines.X64]

-  LIBRARY_CLASS                  = XenHypercallLib|PEIM DXE_DRIVER UEFI_DRIVER

-

-[Defines.ARM, Defines.AARCH64]

   LIBRARY_CLASS                  = XenHypercallLib

 

 #

@@ -52,6 +47,7 @@
   OvmfPkg/OvmfPkg.dec

 

 [LibraryClasses.IA32, LibraryClasses.X64]

+  CpuLib

   BaseLib

   HobLib

   DebugLib