From: stsp <stsp2@yandex.ru>
To: Jim Mattson <jmattson@google.com>
Cc: Sean Christopherson <seanjc@google.com>, kvm@vger.kernel.org
Subject: Re: exception vs SIGALRM race on core2 CPUs (with fix!)
Date: Sun, 27 Jun 2021 15:13:01 +0300 [thread overview]
Message-ID: <6d34acc1-b8cf-b734-c083-dfa446d0a66c@yandex.ru> (raw)
In-Reply-To: <CALMp9eQWKa1vL+jj5HXO1bm+oMo6gQLNw44P7y6ZaF8_WQfukw@mail.gmail.com>
26.06.2021 03:15, Jim Mattson пишет:
> If the squashed exception was a trap, it's now lost.
I am pretty sure this will do it:
---
--- x86.c.old 2021-03-20 12:51:14.000000000 +0300
+++ x86.c 2021-06-27 15:02:45.126161812 +0300
@@ -9093,7 +9093,11 @@
cancel_injection:
if (req_immediate_exit)
kvm_make_request(KVM_REQ_EVENT, vcpu);
- kvm_x86_ops.cancel_injection(vcpu);
+ if (vcpu->arch.exception.injected) {
+ kvm_x86_ops.cancel_injection(vcpu);
+ vcpu->arch.exception.injected = false;
+ vcpu->arch.exception.pending = true;
+ }
if (unlikely(vcpu->arch.apic_attention))
kvm_lapic_sync_from_vapic(vcpu);
out:
@@ -9464,6 +9468,7 @@
kvm_rip_write(vcpu, regs->rip);
kvm_set_rflags(vcpu, regs->rflags | X86_EFLAGS_FIXED);
+ WARN_ON_ONCE(vcpu->arch.exception.injected);
vcpu->arch.exception.pending = false;
kvm_make_request(KVM_REQ_EVENT, vcpu);
---
In cancel_injection, the injected/pending
members were getting out of sync with
vmcs.
We need to move it back to pending,
and if user-space does SET_REGS, then
it is cleared (not sure why SET_SREGS
doesn't clear it also).
But if the .injected member is stuck,
then its not cleared by SET_REGS, and
I added WARN_ON_ONCE() for that case.
Does this make sense?
next prev parent reply other threads:[~2021-06-27 12:13 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-12 22:49 guest/host mem out of sync on core2duo? stsp
2021-06-13 12:36 ` stsp
2021-06-14 17:06 ` Sean Christopherson
2021-06-14 17:32 ` stsp
2021-06-17 14:42 ` Sean Christopherson
2021-06-18 15:59 ` stsp
2021-06-18 21:07 ` Jim Mattson
2021-06-18 21:55 ` stsp
2021-06-18 22:06 ` Jim Mattson
2021-06-18 22:26 ` stsp
2021-06-18 22:32 ` Sean Christopherson
2021-06-19 0:11 ` stsp
2021-06-19 0:54 ` Sean Christopherson
2021-06-19 9:18 ` stsp
2021-06-21 2:34 ` exception vs SIGALRM race (was: Re: guest/host mem out of sync on core2duo?) stsp
2021-06-21 22:33 ` Jim Mattson
2021-06-21 23:32 ` stsp
2021-06-22 0:27 ` stsp
2021-06-28 21:47 ` Jim Mattson
2021-06-28 21:50 ` stsp
2021-06-28 22:00 ` stsp
2021-06-28 22:27 ` Jim Mattson
2021-07-06 16:28 ` Paolo Bonzini
2021-07-06 22:22 ` stsp
2021-07-06 23:41 ` Paolo Bonzini
2021-06-23 23:38 ` exception vs SIGALRM race (with test-case now!) stsp
2021-06-24 0:11 ` stsp
2021-06-24 0:25 ` stsp
2021-06-24 18:05 ` exception vs SIGALRM race on core2 CPUs (with qemu-based test-case this time!) stsp
2021-06-24 18:07 ` stsp
2021-06-25 23:35 ` exception vs SIGALRM race on core2 CPUs (with fix!) stsp
2021-06-26 0:15 ` Jim Mattson
2021-06-26 0:35 ` stsp
2021-06-26 21:50 ` stsp
2021-06-27 12:13 ` stsp [this message]
2021-06-26 14:03 ` exception vs SIGALRM race (another patch) stsp
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=6d34acc1-b8cf-b734-c083-dfa446d0a66c@yandex.ru \
--to=stsp2@yandex.ru \
--cc=jmattson@google.com \
--cc=kvm@vger.kernel.org \
--cc=seanjc@google.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.