From 56d72e41f24f181e244b7f91ed90c248d388d5fa Mon Sep 17 00:00:00 2001
From: Thomas Oltmann <thomas.oltmann.hhg@gmail.com>
Date: Mon, 10 Mar 2025 20:41:09 +0100
Subject: [PATCH] VMCLEAR & VMPTRLD

---
 include/x86/vmx.h | 30 ++++++++++++++++++++++--------
 src/vintel.c      | 17 +++++++++++++++--
 2 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/include/x86/vmx.h b/include/x86/vmx.h
index 1d358c0..729f746 100644
--- a/include/x86/vmx.h
+++ b/include/x86/vmx.h
@@ -10,7 +10,7 @@ struct VMXON {
 };
 
 struct VMCS {
-	int _placeholder;
+	uint32_t revisionID;
 	/* Guest-state area */
 	/* Host-state area */
 	/* VM-execution control fields */
@@ -25,9 +25,9 @@ vmxon(void *region)
 	uint64_t regionpa = (uint64_t)region;
 	uint64_t flags;
 	__asm__ volatile (
-		"vmxon %1\n\t"
-		"pushf   \n\t"
-		"pop   %0\n\t"
+		"vmxon   %1\n\t"
+		"pushf     \n\t"
+		"pop     %0\n\t"
 		: "=r"(flags) : "m"(regionpa));
 	return flags;
 }
@@ -38,10 +38,17 @@ vmxoff(void)
 	__asm__ volatile ("vmxoff\n\t" ::);
 }
 
-static inline void
+static inline uint64_t
 vmptrld(void *region)
 {
-	__asm__ volatile ("vmptrld %0\n\t" :: "r"(region));
+	uint64_t regionpa = (uint64_t)region;
+	uint64_t flags;
+	__asm__ volatile (
+		"vmptrld %1\n\t"
+		"pushf     \n\t"
+		"pop     %0\n\t"
+		: "=r"(flags) : "m"(regionpa));
+	return flags;
 }
 
 static inline void
@@ -50,10 +57,17 @@ vmptrst(void *arg)
 	__asm__ volatile ("vmptrst\n\t" ::);
 }
 
-static inline void
+static inline uint64_t
 vmclear(void *region)
 {
-	__asm__ volatile ("vmclear %0\n\t" :: "r"(region));
+	uint64_t regionpa = (uint64_t)region;
+	uint64_t flags;
+	__asm__ volatile (
+		"vmclear %1\n\t"
+		"pushf     \n\t"
+		"pop     %0\n\t"
+		: "=r"(flags) : "m"(regionpa));
+	return flags;
 }
 
 static inline void
diff --git a/src/vintel.c b/src/vintel.c
index f556a55..c52bc71 100644
--- a/src/vintel.c
+++ b/src/vintel.c
@@ -11,6 +11,7 @@
 #include "std.h"
 
 static struct VMXON *vmxon_region;
+static struct VMCS  *vmcs_region;
 
 static bool
 vintel_has_bios_support(void)
@@ -59,9 +60,8 @@ vintel_enable(void)
 	Print(L"Allocating VMXON Page\n");
 	uefi_call_wrapper(BS->AllocatePages, 4, AllocateAnyPages, EfiRuntimeServicesData, 1, &vmxon_region);
 
-	Print(L"VMCS: %p\n", vmxon_region);
+	Print(L"VMXON: %p\n", vmxon_region);
 	vmxon_region->revisionID = rdmsr32(IA32_VMX_BASIC);
-	Print(L"Set Revision ID.\n");
 
 	uint64_t status = vmxon(vmxon_region);
 	Print(L"VMXON Status: %p\n", (void *)status);
@@ -71,6 +71,19 @@ vintel_enable(void)
 	if (status & (1 << 6)) {
 		Print(L"Extended VMX Error\n");
 	}
+
+
+	Print(L"Allocating VMCS Page\n");
+	uefi_call_wrapper(BS->AllocatePages, 4, AllocateAnyPages, EfiRuntimeServicesData, 1, &vmcs_region);
+
+	Print(L"VMCS: %p\n", vmcs_region);
+	vmcs_region->revisionID = rdmsr32(IA32_VMX_BASIC);
+
+	status = vmclear(vmcs_region);
+	Print(L"VMCLEAR Status: %p\n", (void *)status);
+
+	status = vmptrld(vmcs_region);
+	Print(L"VMPTRLD Status: %p\n", (void *)status);
 }
 
 struct virt_vtable virt_vtable_intel = {