Add the SPEC_CTRL tests for SVM and make sure the settings on L2
guests does not overwrite the L1 guest's SPEC_CTRL settings.
Test Method.
1. Save the L1 guests SPEC_CTRL settings(rdmsr). Normally 0.
2. Start the L2 guest
3. Change the L2 guests SPEC_CTRL settings.
4. Exit the L2 guest.
5. Verify if the settings from step #1 still holds.
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
x86/svm_tests.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 52 insertions(+)
diff --git a/x86/svm_tests.c b/x86/svm_tests.c
index 29a0b59..2867337 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -2002,6 +2002,55 @@ static bool init_intercept_check(struct svm_test *test)
return init_intercept;
}
+/* Indirect Branch Restricted Speculation(bit 0) */
+#define SPEC_CTRL_IBRS 1
+/* Single Thread Indirect Branch Predictor (STIBP)(bit 1) */
+#define SPEC_CTRL_STIBP 2
+/* Speculative Store Bypass Disable (bit 2) */
+#define SPEC_CTRL_SSBD 4
+
+static bool spec_ctrl_supported(void)
+{
+ return this_cpu_has(X86_FEATURE_AMD_SSBD) ||
+ this_cpu_has(X86_FEATURE_AMD_STIBP) ||
+ this_cpu_has(X86_FEATURE_AMD_IBRS);
+}
+
+static void spec_ctrl_prepare(struct svm_test *test)
+{
+ vmcb_ident(vmcb);
+ test->scratch = rdmsr(MSR_IA32_SPEC_CTRL);
+}
+
+/*
+ * Write it twice to bypass the interception. The first write to
+ * SPEC_CTRL is intercepted in older kernels.
+ */
+static void spec_ctrl_test(struct svm_test *test)
+{
+ int spec_ctrl = 0;
+
+ if (this_cpu_has(X86_FEATURE_AMD_SSBD))
+ spec_ctrl |= SPEC_CTRL_SSBD;
+ if (this_cpu_has(X86_FEATURE_AMD_STIBP))
+ spec_ctrl |= SPEC_CTRL_STIBP;
+ if (this_cpu_has(X86_FEATURE_AMD_IBRS))
+ spec_ctrl |= SPEC_CTRL_IBRS;
+
+ wrmsr(MSR_IA32_SPEC_CTRL, spec_ctrl);
+ wrmsr(MSR_IA32_SPEC_CTRL, spec_ctrl);
+}
+
+static bool spec_ctrl_finished(struct svm_test *test)
+{
+ return vmcb->control.exit_code == SVM_EXIT_VMMCALL;
+}
+
+static bool spec_ctrl_check(struct svm_test *test)
+{
+ return test->scratch == rdmsr(MSR_IA32_SPEC_CTRL);
+}
+
#define TEST(name) { #name, .v2 = name }
/*
@@ -2492,6 +2541,9 @@ struct svm_test svm_tests[] = {
{ "svm_init_intercept_test", smp_supported, init_intercept_prepare,
default_prepare_gif_clear, init_intercept_test,
init_intercept_finished, init_intercept_check, .on_vcpu = 2 },
+ { "SPEC_CTRL", spec_ctrl_supported, spec_ctrl_prepare,
+ default_prepare_gif_clear, spec_ctrl_test,
+ spec_ctrl_finished, spec_ctrl_check },
TEST(svm_cr4_osxsave_test),
TEST(svm_guest_state_test),
TEST(svm_vmrun_errata_test),
