target/i386: check validity of VMCB addresses

MSR_VM_HSAVE_PA bits 0-11 are reserved, as are the bits above the
maximum physical address width of the processor.  Setting them to
1 causes a #GP (see "15.30.4 VM_HSAVE_PA MSR" in the AMD manual).

The same is true of VMCB addresses passed to VMRUN/VMLOAD/VMSAVE,
even though the manual is not clear on that.

Cc: qemu-stable@nongnu.org
Fixes: 4a1e9d4d11c ("target/i386: Use atomic operations for pte updates", 2022-10-18)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 21 insertions, 6 deletions

diff --git a/target/i386/tcg/sysemu/svm_helper.c b/target/i386/tcg/sysemu/svm_helper.c
index 32ff0db..5d6de22 100644
--- a/target/i386/tcg/sysemu/svm_helper.c
+++ b/target/i386/tcg/sysemu/svm_helper.c
@@ -164,14 +164,19 @@ void helper_vmrun(CPUX86State *env, int aflag, int next_eip_addend)
     uint64_t new_cr3;
     uint64_t new_cr4;
 
-    cpu_svm_check_intercept_param(env, SVM_EXIT_VMRUN, 0, GETPC());
-
     if (aflag == 2) {
         addr = env->regs[R_EAX];
     } else {
         addr = (uint32_t)env->regs[R_EAX];
     }
 
+    /* Exceptions are checked before the intercept.  */
+    if (addr & (0xfff | ((~0ULL) << env_archcpu(env)->phys_bits))) {
+        raise_exception_err_ra(env, EXCP0D_GPF, 0, GETPC());
+    }
+
+    cpu_svm_check_intercept_param(env, SVM_EXIT_VMRUN, 0, GETPC());
+
     qemu_log_mask(CPU_LOG_TB_IN_ASM, "vmrun! " TARGET_FMT_lx "\n", addr);
 
     env->vm_vmcb = addr;
@@ -463,14 +468,19 @@ void helper_vmload(CPUX86State *env, int aflag)
     int mmu_idx = MMU_PHYS_IDX;
     target_ulong addr;
 
-    cpu_svm_check_intercept_param(env, SVM_EXIT_VMLOAD, 0, GETPC());
-
     if (aflag == 2) {
         addr = env->regs[R_EAX];
     } else {
         addr = (uint32_t)env->regs[R_EAX];
     }
 
+    /* Exceptions are checked before the intercept.  */
+    if (addr & (0xfff | ((~0ULL) << env_archcpu(env)->phys_bits))) {
+        raise_exception_err_ra(env, EXCP0D_GPF, 0, GETPC());
+    }
+
+    cpu_svm_check_intercept_param(env, SVM_EXIT_VMLOAD, 0, GETPC());
+
     if (virtual_vm_load_save_enabled(env, SVM_EXIT_VMLOAD, GETPC())) {
         mmu_idx = MMU_NESTED_IDX;
     }
@@ -519,14 +529,19 @@ void helper_vmsave(CPUX86State *env, int aflag)
     int mmu_idx = MMU_PHYS_IDX;
     target_ulong addr;
 
-    cpu_svm_check_intercept_param(env, SVM_EXIT_VMSAVE, 0, GETPC());
-
     if (aflag == 2) {
         addr = env->regs[R_EAX];
     } else {
         addr = (uint32_t)env->regs[R_EAX];
     }
 
+    /* Exceptions are checked before the intercept.  */
+    if (addr & (0xfff | ((~0ULL) << env_archcpu(env)->phys_bits))) {
+        raise_exception_err_ra(env, EXCP0D_GPF, 0, GETPC());
+    }
+
+    cpu_svm_check_intercept_param(env, SVM_EXIT_VMSAVE, 0, GETPC());
+
     if (virtual_vm_load_save_enabled(env, SVM_EXIT_VMSAVE, GETPC())) {
         mmu_idx = MMU_NESTED_IDX;
     }