linux-kernel - [PATCH 5.12 073/127] x86/sev-es: Forward page-faults which happen during emulation

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Date:   Mon, 24 May 2021 17:26:30 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Joerg Roedel <jroedel@...e.de>,
        Borislav Petkov <bp@...e.de>
Subject: [PATCH 5.12 073/127] x86/sev-es: Forward page-faults which happen during emulation

From: Joerg Roedel <jroedel@...e.de>

commit c25bbdb564060adaad5c3a8a10765c13487ba6a3 upstream.

When emulating guest instructions for MMIO or IOIO accesses, the #VC
handler might get a page-fault and will not be able to complete. Forward
the page-fault in this case to the correct handler instead of killing
the machine.

Fixes: 0786138c78e7 ("x86/sev-es: Add a Runtime #VC Exception Handler")
Signed-off-by: Joerg Roedel <jroedel@...e.de>
Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: stable@...r.kernel.org # v5.10+
Link: https://lkml.kernel.org/r/20210519135251.30093-3-joro@8bytes.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/kernel/sev-es.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -1269,6 +1269,10 @@ static __always_inline void vc_forward_e
 	case X86_TRAP_UD:
 		exc_invalid_op(ctxt->regs);
 		break;
+	case X86_TRAP_PF:
+		write_cr2(ctxt->fi.cr2);
+		exc_page_fault(ctxt->regs, error_code);
+		break;
 	case X86_TRAP_AC:
 		exc_alignment_check(ctxt->regs, error_code);
 		break;