From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Jan Dakinevich <jan.dakinevich@virtuozzo.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Denis Lunev" <den@virtuozzo.com>,
"Roman Kagan" <rkagan@virtuozzo.com>,
"Denis Plotnikov" <dplotnikov@virtuozzo.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
"Wanpeng Li" <wanpengli@tencent.com>,
"Jim Mattson" <jmattson@google.com>,
"Joerg Roedel" <joro@8bytes.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
"x86@kernel.org" <x86@kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [PATCH 2/3] KVM: x86: set ctxt->have_exception in x86_decode_insn()
Date: Tue, 27 Aug 2019 07:53:58 -0700 [thread overview]
Message-ID: <20190827145358.GD27459@linux.intel.com> (raw)
In-Reply-To: <1566911210-30059-3-git-send-email-jan.dakinevich@virtuozzo.com>
On Tue, Aug 27, 2019 at 01:07:08PM +0000, Jan Dakinevich wrote:
> x86_emulate_instruction() takes into account ctxt->have_exception flag
> during instruction decoding, but in practice this flag is never set in
> x86_decode_insn().
>
> Fixes: 6ea6e84 ("KVM: x86: inject exceptions produced by x86_decode_insn")
> Cc: Denis Lunev <den@virtuozzo.com>
> Cc: Roman Kagan <rkagan@virtuozzo.com>
> Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
> Signed-off-by: Jan Dakinevich <jan.dakinevich@virtuozzo.com>
> ---
> arch/x86/kvm/emulate.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 6170ddf..f93880f 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -5395,6 +5395,8 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
> ctxt->memopp->addr.mem.ea + ctxt->_eip);
>
> done:
> + if (rc == X86EMUL_PROPAGATE_FAULT)
> + ctxt->have_exception = true;
We should add a sanity check or two on the vector since the emulator code
goes all over the place, e.g. #UD should not be injected/propagated, and
trap-like exceptions should not be handled/encountered during decode.
Note, exception_type() also warns on illegal vectors.
WARN_ON_ONCE(ctxt->exception.vector == UD_VECTOR ||
exception_type(ctxt->exception.vector) == EXCPT_TRAP);
> return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK;
> }
>
> --
> 2.1.4
>
next prev parent reply other threads:[~2019-08-27 14:54 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-27 13:07 [PATCH 0/3] fix emulation error on Windows bootup Jan Dakinevich
2019-08-27 13:07 ` [PATCH 1/3] KVM: x86: fix wrong return code Jan Dakinevich
2019-08-27 13:42 ` Sean Christopherson
2019-08-27 13:07 ` [PATCH 2/3] KVM: x86: set ctxt->have_exception in x86_decode_insn() Jan Dakinevich
2019-08-27 14:53 ` Sean Christopherson [this message]
2019-08-28 10:19 ` Jan Dakinevich
2019-08-27 13:07 ` [PATCH 3/3] KVM: x86: always stop emulation on page fault Jan Dakinevich
2019-08-27 14:50 ` Sean Christopherson
2019-08-27 14:55 ` Sean Christopherson
2019-08-28 10:19 ` Jan Dakinevich
2019-08-28 14:23 ` Sean Christopherson
2019-09-11 15:51 ` [PATCH 0/3] fix emulation error on Windows bootup Paolo Bonzini
2019-09-11 19:53 ` Sean Christopherson
2019-09-13 9:51 ` Paolo Bonzini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190827145358.GD27459@linux.intel.com \
--to=sean.j.christopherson@intel.com \
--cc=bp@alien8.de \
--cc=den@virtuozzo.com \
--cc=dplotnikov@virtuozzo.com \
--cc=hpa@zytor.com \
--cc=jan.dakinevich@virtuozzo.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=rkagan@virtuozzo.com \
--cc=rkrcmar@redhat.com \
--cc=tglx@linutronix.de \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).