Messages in this thread Patch in this message | | | From | Tom Lendacky <> | Subject | [PATCH] x86/sev-es: Do not unroll string I/O for SEV-ES guests | Date | Mon, 1 Feb 2021 12:26:27 -0600 |
| |
From: Tom Lendacky <thomas.lendacky@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.lendacky@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
| |