From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, llvm@lists.linux.dev,
linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
syzbot+6cde2282daa792c49ab8@syzkaller.appspotmail.com
Subject: [PATCH 5/5] KVM: x86: Bail to userspace if emulation of atomic user access faults
Date: Tue, 1 Feb 2022 01:08:38 +0000 [thread overview]
Message-ID: <20220201010838.1494405-6-seanjc@google.com> (raw)
In-Reply-To: <20220201010838.1494405-1-seanjc@google.com>
Exit to userspace when emulating an atomic guest access if the CMPXCHG on
the userspace address faults. Emulating the access as a write and thus
likely treating it as emulated MMIO is wrong, as KVM has already
confirmed there is a valid, writable memslot.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/x86.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 37064d565bbc..66c5410dd4c3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7217,7 +7217,7 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
}
if (r < 0)
- goto emul_write;
+ return X86EMUL_UNHANDLEABLE;
if (r)
return X86EMUL_CMPXCHG_FAILED;
--
2.35.0.rc2.247.g8bbb082509-goog
next prev parent reply other threads:[~2022-02-01 1:09 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-01 1:08 [PATCH 0/5] x86: uaccess CMPXCHG + KVM bug fixes Sean Christopherson
2022-02-01 1:08 ` [PATCH 1/5] Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug Sean Christopherson
2022-02-01 20:16 ` Nick Desaulniers
2022-02-01 20:56 ` Sean Christopherson
2022-02-01 21:15 ` Nick Desaulniers
2022-02-01 1:08 ` [PATCH 2/5] x86/uaccess: Implement macros for CMPXCHG on user addresses Sean Christopherson
2022-02-01 1:08 ` [PATCH 3/5] KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits Sean Christopherson
2022-02-01 7:01 ` kernel test robot
2022-02-01 19:44 ` Sean Christopherson
2022-02-01 19:53 ` Nick Desaulniers
2022-02-01 13:25 ` kernel test robot
2022-02-01 1:08 ` [PATCH 4/5] KVM: x86: Use __try_cmpxchg_user() to emulate atomic accesses Sean Christopherson
2022-02-01 9:25 ` kernel test robot
2022-02-01 1:08 ` Sean Christopherson [this message]
2022-02-01 17:09 ` [PATCH 0/5] x86: uaccess CMPXCHG + KVM bug fixes Tadeusz Struk
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