From: Tom Lendacky <thomas.lenda...@amd.com>
Under the GHCB specification, SEV-ES guests can support string I/O. The
current #VC handler contains this support, so remove the need to unroll
kernel string I/O operations. This will reduce the number of #VC
exceptions generated as well as the number VMEXITS for the guest.
Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com>
---
arch/x86/mm/mem_encrypt.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index c79e5736ab2b..d55ea77e1ca8 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -474,9 +474,10 @@ void __init mem_encrypt_init(void)
swiotlb_update_mem_attributes();
/*
- * With SEV, we need to unroll the rep string I/O instructions.
+ * With SEV, we need to unroll the rep string I/O instructions,
+ * but SEV-ES supports them through the #VC handler.
*/
- if (sev_active())
+ if (sev_active() && !sev_es_active())
static_branch_enable(&sev_enable_key);
print_mem_encrypt_feature_info();
base-commit: a7e0bdf1b07ea6169930ec42b0bdb17e1c1e3bb0
--
2.30.0
