[PATCH 0/3] KVM: x86: Fix fault-related bugs in LTR/LLDT emulation

From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	syzbot+760a73552f47a8cd0fd9@syzkaller.appspotmail.com,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Hou Wenlong <houwenlong.hwl@antgroup.com>
Subject: [PATCH 0/3] KVM: x86: Fix fault-related bugs in LTR/LLDT emulation
Date: Mon, 11 Jul 2022 23:27:47 +0000	[thread overview]
Message-ID: <20220711232750.1092012-1-seanjc@google.com> (raw)

Patch 1 fixes a bug found by syzkaller where KVM attempts to set the
TSS.busy bit during LTR before checking that the new TSS.base is valid.

Patch 2 fixes a bug found by inspection (when reading the APM to verify
the non-canonical logic is correct) where KVM doesn't provide the correct
error code if the new TSS.base is non-canonical.

Patch 3 makes the "dangling userspace I/O" WARN_ON two separate WARN_ON_ONCE
so that a KVM bug doesn't spam the kernel log (keeping the WARN is desirable
specifically to detect these types of bugs).

Sean Christopherson (3):
  KVM: x86: Mark TSS busy during LTR emulation _after_ all fault checks
  KVM: x86: Set error code to segment selector on LLDT/LTR non-canonical
    #GP
  KVM: x86: WARN only once if KVM leaves a dangling userspace I/O
    request

 arch/x86/kvm/emulate.c | 23 +++++++++++------------
 arch/x86/kvm/x86.c     |  6 ++++--
 2 files changed, 15 insertions(+), 14 deletions(-)

base-commit: b9b71f43683ae9d76b0989249607bbe8c9eb6c5c
-- 
2.37.0.144.g8ac04bfd2-goog