linux-kernel - [tip: x86/urgent] x86/sev-es: Forward page-faults which happen during emulation

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Date:   Thu, 20 May 2021 10:22:18 -0000
From:   "tip-bot2 for Joerg Roedel" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Joerg Roedel <jroedel@...e.de>, Borislav Petkov <bp@...e.de>,
        stable@...r.kernel.org, #@...-bot2.tec.linutronix.de,
        v5.10+@...-bot2.tec.linutronix.de, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/urgent] x86/sev-es: Forward page-faults which happen during
 emulation

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     c25bbdb564060adaad5c3a8a10765c13487ba6a3
Gitweb:        https://git.kernel.org/tip/c25bbdb564060adaad5c3a8a10765c13487ba6a3
Author:        Joerg Roedel <jroedel@...e.de>
AuthorDate:    Wed, 19 May 2021 15:52:45 +02:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Wed, 19 May 2021 17:13:04 +02:00

x86/sev-es: Forward page-faults which happen during emulation

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
---
 arch/x86/kernel/sev.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 82bced8..1f428f4 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1270,6 +1270,10 @@ 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_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;