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From: "tip-bot2 for Joerg Roedel" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Joerg Roedel <jroedel@suse.de>, Borislav Petkov <bp@suse.de>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: x86/sev] x86/sev: Propagate #GP if getting linear instruction address failed
Date: Tue, 15 Jun 2021 10:51:55 -0000	[thread overview]
Message-ID: <162375431608.19906.8487681008973797088.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210614135327.9921-7-joro@8bytes.org>

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

Commit-ID:     07570cef5e5c3fcec40f82a9075abb4c1da63319
Gitweb:        https://git.kernel.org/tip/07570cef5e5c3fcec40f82a9075abb4c1da63319
Author:        Joerg Roedel <jroedel@suse.de>
AuthorDate:    Mon, 14 Jun 2021 15:53:27 +02:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Tue, 15 Jun 2021 11:55:26 +02:00

x86/sev: Propagate #GP if getting linear instruction address failed

When an instruction is fetched from user-space, segmentation needs to
be taken into account. This means that getting the linear address of an
instruction can fail. Hardware would raise a #GP exception in that case,
but the #VC exception handler would emulate it as a page-fault.

The insn_fetch_from_user*() functions now provide the relevant
information in case of a failure. Use that and propagate a #GP when the
linear address of an instruction to fetch could not be calculated.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210614135327.9921-7-joro@8bytes.org
---
 arch/x86/kernel/sev.c |  9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index a1eeaa7..8178db0 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -261,11 +261,18 @@ static enum es_result __vc_decode_user_insn(struct es_em_ctxt *ctxt)
 	int insn_bytes;
 
 	insn_bytes = insn_fetch_from_user_inatomic(ctxt->regs, buffer);
-	if (insn_bytes <= 0) {
+	if (insn_bytes == 0) {
+		/* Nothing could be copied */
 		ctxt->fi.vector     = X86_TRAP_PF;
 		ctxt->fi.error_code = X86_PF_INSTR | X86_PF_USER;
 		ctxt->fi.cr2        = ctxt->regs->ip;
 		return ES_EXCEPTION;
+	} else if (insn_bytes == -EINVAL) {
+		/* Effective RIP could not be calculated */
+		ctxt->fi.vector     = X86_TRAP_GP;
+		ctxt->fi.error_code = 0;
+		ctxt->fi.cr2        = 0;
+		return ES_EXCEPTION;
 	}
 
 	if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, insn_bytes))

      reply	other threads:[~2021-06-15 10:52 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-14 13:53 [PATCH v5 0/6] x86/sev-es: Fixes for SEV-ES Guest Support Joerg Roedel
2021-06-14 13:53 ` Joerg Roedel
2021-06-14 13:53 ` [PATCH v5 1/6] x86/sev-es: Fix error message in runtime #VC handler Joerg Roedel
2021-06-14 13:53   ` Joerg Roedel
2021-06-15 10:51   ` [tip: x86/sev] x86/sev: " tip-bot2 for Joerg Roedel
2021-06-14 13:53 ` [PATCH v5 2/6] x86/sev-es: Make sure IRQs are disabled while GHCB is active Joerg Roedel
2021-06-14 13:53   ` Joerg Roedel
2021-06-14 16:25   ` Borislav Petkov
2021-06-14 16:25     ` Borislav Petkov
2021-06-14 16:30     ` Borislav Petkov
2021-06-14 16:30       ` Borislav Petkov
2021-06-15  9:37     ` Joerg Roedel
2021-06-15  9:37       ` Joerg Roedel
2021-06-14 13:53 ` [PATCH v5 3/6] x86/sev-es: Split up runtime #VC handler for correct state tracking Joerg Roedel
2021-06-14 13:53   ` Joerg Roedel
2021-06-16 16:04   ` Peter Zijlstra
2021-06-16 16:04     ` Peter Zijlstra
2021-06-16 19:01     ` Joerg Roedel
2021-06-16 19:01       ` Joerg Roedel
2021-06-14 13:53 ` [PATCH v5 4/6] x86/insn-eval: Make 0 a valid RIP for insn_get_effective_ip() Joerg Roedel
2021-06-14 13:53   ` Joerg Roedel
2021-06-15 10:51   ` [tip: x86/sev] " tip-bot2 for Joerg Roedel
2021-06-14 13:53 ` [PATCH v5 5/6] x86/insn: Extend error reporting from insn_fetch_from_user[_inatomic]() Joerg Roedel
2021-06-14 13:53   ` Joerg Roedel
2021-06-15 10:51   ` [tip: x86/sev] " tip-bot2 for Joerg Roedel
2021-06-14 13:53 ` [PATCH v5 6/6] x86/sev-es: Propagate #GP if getting linear instruction address failed Joerg Roedel
2021-06-14 13:53   ` Joerg Roedel
2021-06-15 10:51   ` tip-bot2 for Joerg Roedel [this message]

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