[PATCH kernel 3/3] x86/sev: Do not handle #VC for DR7 read/write

[Alexey Kardashevskiy]

With SVM_SEV_FEAT_DEBUG_SWAP enabled, the VM should not get #VC events
for DR7 read/write which it rather avoided.

Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxx>
---
 arch/x86/kernel/sev.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index a428c62330d3..4e91b9f8742c 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1618,6 +1618,9 @@ static enum es_result vc_handle_dr7_write(struct ghcb *ghcb,
 	long val, *reg = vc_insn_get_rm(ctxt);
 	enum es_result ret;
 
+	if ((sev_status >> 2) & SVM_SEV_FEAT_DEBUG_SWAP)
+		return ES_VMM_ERROR;
+
 	if (!reg)
 		return ES_DECODE_FAILED;
 
@@ -1655,6 +1658,9 @@ static enum es_result vc_handle_dr7_read(struct ghcb *ghcb,
 	struct sev_es_runtime_data *data = this_cpu_read(runtime_data);
 	long *reg = vc_insn_get_rm(ctxt);
 
+	if ((sev_status >> 2) & SVM_SEV_FEAT_DEBUG_SWAP)
+		return ES_VMM_ERROR;
+
 	if (!reg)
 		return ES_DECODE_FAILED;
 
-- 
2.38.1