Commit a2d0171a authored by Joerg Roedel's avatar Joerg Roedel Committed by Borislav Petkov
Browse files

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: default avatarJoerg Roedel <jroedel@suse.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-61-joro@8bytes.org
parent 2eb7dcf0

arch/x86/kernel/sev-es.c

+19 −0
Original line number Diff line number Diff line
@@ -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();

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