linux-kernel - [PATCH 0/3] fix emulation error on Windows bootup

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Date:   Tue, 27 Aug 2019 13:07:00 +0000
From:   Jan Dakinevich <jan.dakinevich@...tuozzo.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Jan Dakinevich <jan.dakinevich@...tuozzo.com>,
        Denis Lunev <den@...tuozzo.com>,
        Roman Kagan <rkagan@...tuozzo.com>,
        Denis Plotnikov <dplotnikov@...tuozzo.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>
Subject: [PATCH 0/3] fix emulation error on Windows bootup

This series intended to fix (again) a bug that was a subject of the 
following change:

  6ea6e84 ("KVM: x86: inject exceptions produced by x86_decode_insn")

Suddenly, that fix had a couple mistakes. First, ctxt->have_exception was 
not set if fault happened during instruction decoding. Second, returning 
value of inject_emulated_instruction was used to make the decision to 
reenter guest, but this could happen iff on nested page fault, that is not 
the scope where this bug could occur.

However, I have still deep doubts about 3rd commit in the series. Could
you please, make me an advise if it is the correct handling of guest page 
fault?

Jan Dakinevich (3):
  KVM: x86: fix wrong return code
  KVM: x86: set ctxt->have_exception in x86_decode_insn()
  KVM: x86: always stop emulation on page fault

 arch/x86/kvm/emulate.c | 4 +++-
 arch/x86/kvm/x86.c     | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

-- 
2.1.4