From a2d0171a9cf59637411281a929900fde80e6c1cb Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Mon, 7 Sep 2020 15:16:01 +0200 Subject: [PATCH] x86/sev-es: Handle #AC Events Implement a handler for #VC exceptions caused by #AC exceptions. The #AC exception is just forwarded to do_alignment_check() and not pushed down to the hypervisor, as requested by the SEV-ES GHCB Standardization Specification. Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200907131613.12703-61-joro@8bytes.org --- arch/x86/kernel/sev-es.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index 86cb4c5..8867c48 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -909,6 +909,19 @@ static enum es_result vc_handle_vmmcall(struct ghcb *ghcb, return ES_OK; } +static enum es_result vc_handle_trap_ac(struct ghcb *ghcb, + struct es_em_ctxt *ctxt) +{ + /* + * Calling ecx_alignment_check() directly does not work, because it + * enables IRQs and the GHCB is active. Forward the exception and call + * it later from vc_forward_exception(). + */ + ctxt->fi.vector = X86_TRAP_AC; + ctxt->fi.error_code = 0; + return ES_EXCEPTION; +} + static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt, struct ghcb *ghcb, unsigned long exit_code) @@ -922,6 +935,9 @@ static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt, case SVM_EXIT_WRITE_DR7: result = vc_handle_dr7_write(ghcb, ctxt); break; + case SVM_EXIT_EXCP_BASE + X86_TRAP_AC: + result = vc_handle_trap_ac(ghcb, ctxt); + break; case SVM_EXIT_RDTSC: case SVM_EXIT_RDTSCP: result = vc_handle_rdtsc(ghcb, ctxt, exit_code); @@ -981,6 +997,9 @@ static __always_inline void vc_forward_exception(struct es_em_ctxt *ctxt) case X86_TRAP_UD: exc_invalid_op(ctxt->regs); break; + case X86_TRAP_AC: + exc_alignment_check(ctxt->regs, error_code); + break; default: pr_emerg("Unsupported exception in #VC instruction emulation - can't continue\n"); BUG(); -- 2.7.4