On 18/10/21 13:47, Varad Gautam wrote:
Hi Zixuan,
On 10/4/21 10:49 PM, Zixuan Wang wrote:
From: Zixuan Wang <zixuanwang@xxxxxxxxxx>
SEV-ES introduces #VC handler for guest/host communications, e.g.,
accessing MSR, executing CPUID. This commit provides test cases to check
if SEV-ES is enabled and if rdmsr/wrmsr are handled correctly in SEV-ES.
Signed-off-by: Zixuan Wang <zixuanwang@xxxxxxxxxx>
---
x86/amd_sev.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/x86/amd_sev.c b/x86/amd_sev.c
index a07a48f..21a491c 100644
--- a/x86/amd_sev.c
+++ b/x86/amd_sev.c
@@ -13,6 +13,7 @@
#include "libcflat.h"
#include "x86/processor.h"
#include "x86/amd_sev.h"
+#include "msr.h"
#define EXIT_SUCCESS 0
#define EXIT_FAILURE 1
@@ -55,10 +56,39 @@ static int test_sev_activation(void)
return EXIT_SUCCESS;
}
+static int test_sev_es_activation(void)
+{
+ if (!(rdmsr(MSR_SEV_STATUS) & SEV_ES_ENABLED_MASK)) {
+ return EXIT_FAILURE;
+ }
+
+ return EXIT_SUCCESS;
+}
+
+static int test_sev_es_msr(void)
+{
+ /*
+ * With SEV-ES, rdmsr/wrmsr trigger #VC exception. If #VC is handled
+ * correctly, rdmsr/wrmsr should work like without SEV-ES and not crash
+ * the guest VM.
+ */
+ u64 val = 0x1234;
+ wrmsr(MSR_TSC_AUX, val);
+ if(val != rdmsr(MSR_TSC_AUX)) {
+ return EXIT_FAILURE;
See note below.
+ }
+
+ return EXIT_SUCCESS;
+}
+
int main(void)
{
int rtn;
rtn = test_sev_activation();
report(rtn == EXIT_SUCCESS, "SEV activation test.");
+ rtn = test_sev_es_activation();
+ report(rtn == EXIT_SUCCESS, "SEV-ES activation test.");
+ rtn = test_sev_es_msr();
There is nothing SEV-ES specific about this function, it only wraps
rdmsr/wrmsr, which are supposed to generate #VC exceptions on SEV-ES.
Since the same scenario can be covered by running the msr testcase
as a SEV-ES guest and observing if it crashes, does testing
rdmsr/wrmsr one more time here gain us any new information?
Also, the function gets called from main() even if
test_sev_es_activation() failed or SEV-ES was inactive.
Agreed, this patch is still a bit rough. However, a very simple change
to report whether SEV-ES is enabled is a good addition to x86/amd_sev.c
Paolo
