[PULL 40/48] target/i386: Added DR6 and DR7 consistency checks

[Paolo Bonzini]

From: Lara Lazier <laramglazier@gmail.com>

DR6[63:32] and DR7[63:32] are reserved and need to be zero.
(AMD64 Architecture Programmer's Manual, V2, 15.5)

Signed-off-by: Lara Lazier <laramglazier@gmail.com>
Message-Id: <20210705081802.18960-3-laramglazier@gmail.com>
[Ignore for 32-bit builds. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/svm.h                   | 2 ++
 target/i386/tcg/sysemu/svm_helper.c | 9 ++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/target/i386/svm.h b/target/i386/svm.h
index adc058dc76..4bde9f3475 100644
--- a/target/i386/svm.h
+++ b/target/i386/svm.h
@@ -140,6 +140,8 @@
 #define SVM_MSRPM_SIZE         (1ULL << 13)
 #define SVM_IOPM_SIZE          ((1ULL << 13) + 1)
 
+#define SVM_DR_RESERVED_MASK 0xffffffff00000000ULL
+
 struct QEMU_PACKED vmcb_control_area {
        uint16_t intercept_cr_read;
        uint16_t intercept_cr_write;
diff --git a/target/i386/tcg/sysemu/svm_helper.c 
b/target/i386/tcg/sysemu/svm_helper.c
index fa701829e5..047f31628e 100644
--- a/target/i386/tcg/sysemu/svm_helper.c
+++ b/target/i386/tcg/sysemu/svm_helper.c
@@ -269,7 +269,14 @@ void helper_vmrun(CPUX86State *env, int aflag, int 
next_eip_addend)
     env->dr[6] = x86_ldq_phys(cs,
                           env->vm_vmcb + offsetof(struct vmcb, save.dr6));
 
-    /* FIXME: guest state consistency checks */
+#ifdef TARGET_X86_64
+    if (env->dr[6] & SVM_DR_RESERVED_MASK) {
+        cpu_vmexit(env, SVM_EXIT_ERR, 0, GETPC());
+    }
+    if (env->dr[7] & SVM_DR_RESERVED_MASK) {
+        cpu_vmexit(env, SVM_EXIT_ERR, 0, GETPC());
+    }
+#endif
 
     switch (x86_ldub_phys(cs,
                       env->vm_vmcb + offsetof(struct vmcb, control.tlb_ctl))) {
-- 
2.31.1