@@ -192,6 +192,10 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
if (result != ES_OK)
goto finish;
+ result = vc_check_opcode_bytes(&ctxt, exit_code);
+ if (result != ES_OK)
+ goto finish;
+
switch (exit_code) {
case SVM_EXIT_RDTSC:
case SVM_EXIT_RDTSCP:
@@ -10,8 +10,13 @@
*/
#ifndef __BOOT_COMPRESSED
-#define error(v) pr_err(v)
-#define has_cpuflag(f) boot_cpu_has(f)
+#define error(v) pr_err(v)
+#define has_cpuflag(f) boot_cpu_has(f)
+#define sev_printk(fmt, ...) printk(fmt, ##__VA_ARGS__)
+#define sev_printk_rtl(fmt, ...) printk_ratelimited(fmt, ##__VA_ARGS__)
+#else
+#define sev_printk(fmt, ...)
+#define sev_printk_rtl(fmt, ...)
#endif
static bool __init sev_es_check_cpu_features(void)
@@ -148,11 +153,16 @@ void __init do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code)
{
unsigned int fn = lower_bits(regs->ax, 32);
unsigned long val;
+ u16 opcode = *(unsigned short *)regs->ip;
/* Only CPUID is supported via MSR protocol */
if (exit_code != SVM_EXIT_CPUID)
goto fail;
+ /* Is it really a CPUID insn? */
+ if (opcode != 0xa20f)
+ goto fail;
+
sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(fn, GHCB_CPUID_REQ_EAX));
VMGEXIT();
val = sev_es_rd_ghcb_msr();
@@ -561,3 +571,92 @@ static enum es_result vc_handle_rdtsc(struct ghcb *ghcb,
return ES_OK;
}
+
+static enum es_result vc_check_opcode_bytes(struct es_em_ctxt *ctxt,
+ unsigned long exit_code)
+{
+ unsigned int opcode = (unsigned int)ctxt->insn.opcode.value;
+ u8 modrm = ctxt->insn.modrm.value;
+
+ switch (exit_code) {
+
+ case SVM_EXIT_IOIO:
+ case SVM_EXIT_NPF:
+ /* handled separately */
+ return ES_OK;
+
+ case SVM_EXIT_CPUID:
+ if (opcode == 0xa20f)
+ return ES_OK;
+ break;
+
+ case SVM_EXIT_INVD:
+ if (opcode == 0x080f)
+ return ES_OK;
+ break;
+
+ case SVM_EXIT_MONITOR:
+ if (opcode == 0x010f && modrm == 0xc8)
+ return ES_OK;
+ break;
+
+ case SVM_EXIT_MWAIT:
+ if (opcode == 0x010f && modrm == 0xc9)
+ return ES_OK;
+ break;
+
+ case SVM_EXIT_MSR:
+ /* RDMSR */
+ if (opcode == 0x320f ||
+ /* WRMSR */
+ opcode == 0x300f)
+ return ES_OK;
+ break;
+
+ case SVM_EXIT_RDPMC:
+ if (opcode == 0x330f)
+ return ES_OK;
+ break;
+
+ case SVM_EXIT_RDTSC:
+ if (opcode == 0x310f)
+ return ES_OK;
+ break;
+
+ case SVM_EXIT_RDTSCP:
+ if (opcode == 0x010f && modrm == 0xf9)
+ return ES_OK;
+ break;
+
+ case SVM_EXIT_READ_DR7:
+ if (opcode == 0x210f &&
+ X86_MODRM_REG(ctxt->insn.modrm.value) == 7)
+ return ES_OK;
+ break;
+
+ case SVM_EXIT_VMMCALL:
+ if (opcode == 0x010f && modrm == 0xd9)
+ return ES_OK;
+
+ break;
+
+ case SVM_EXIT_WRITE_DR7:
+ if (opcode == 0x230f &&
+ X86_MODRM_REG(ctxt->insn.modrm.value) == 7)
+ return ES_OK;
+ break;
+
+ case SVM_EXIT_WBINVD:
+ if (opcode == 0x90f)
+ return ES_OK;
+ break;
+
+ default:
+ break;
+ }
+
+ sev_printk(KERN_ERR "Wrong/unhandled opcode bytes: 0x%x, exit_code: 0x%lx, rIP: 0x%lx\n",
+ opcode, exit_code, ctxt->regs->ip);
+
+ return ES_UNSUPPORTED;
+}
@@ -1254,7 +1254,10 @@ static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt,
struct ghcb *ghcb,
unsigned long exit_code)
{
- enum es_result result;
+ enum es_result result = vc_check_opcode_bytes(ctxt, exit_code);
+
+ if (result != ES_OK)
+ return result;
switch (exit_code) {
case SVM_EXIT_READ_DR7: