[PATCH 52/70] x86/sev-es: Handle RDTSC Events

Joerg Roedel
2020-03-19T09:16:44Z

From: Tom Lendacky <thomas.lendacky@amd.com>

Implement a handler for #VC exceptions caused by RDTSC instructions.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
[ jroedel@suse.de: Adapt to #VC handling infrastructure ]
Co-developed-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/kernel/sev-es.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
index 5b024ee54307..afbe574126f3 100644
--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -665,6 +665,23 @@ static enum es_result vc_handle_wbinvd(struct ghcb *ghcb,
return sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_WBINVD, 0, 0);
}

+static enum es_result vc_handle_rdtsc(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
+{
+ enum es_result ret;
+
+ ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_RDTSC, 0, 0);
+ if (ret != ES_OK)
+ return ret;
+
+ if (!(ghcb_is_valid_rax(ghcb) && ghcb_is_valid_rdx(ghcb)))
+ return ES_VMM_ERROR;
+
+ ctxt->regs->ax = ghcb->save.rax;
+ ctxt->regs->dx = ghcb->save.rdx;
+
+ return ES_OK;
+}
+
static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt,
struct ghcb *ghcb,
unsigned long exit_code,
@@ -679,6 +696,9 @@ static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt,
case SVM_EXIT_WRITE_DR7:
result = vc_handle_dr7_write(ghcb, ctxt, early);
break;
+ case SVM_EXIT_RDTSC:
+ result = vc_handle_rdtsc(ghcb, ctxt);
+ break;
case SVM_EXIT_CPUID:
result = vc_handle_cpuid(ghcb, ctxt);
break;
--
2.17.1