From: Marcelo Tosatti <mtosatti@redhat.com>
To: kvm <kvm@vger.kernel.org>
Cc: Avi Kivity <avi@redhat.com>,
Nicolas Prochazka <prochazka.nicolas@gmail.com>
Subject: KVM: MMU: update sp->gfns on pte update path
Date: Tue, 25 Jan 2011 11:07:33 -0200 [thread overview]
Message-ID: <20110125130733.GA5645@amt.cnet> (raw)
If an emulated pte write modifies the gpa of a present spte, sp->gfns is
not updated, retaining a stale value which later leads to:
rmap_remove: ffff8807d245fff8 0->BUG
------------[ cut here ]------------
kernel BUG at arch/x86/kvm/mmu.c:695!
Fix by updating sp->gfns even if spte was present.
Resolves: https://bugzilla.kernel.org/show_bug.cgi?id=27052
Reported-and-tested-by: Nicolas Prochazka <prochazka.nicolas@gmail.com>
KVM-Stable-Tag.
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index cc1bada..37d0886 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2054,6 +2054,12 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
rmap_count = rmap_add(vcpu, sptep, gfn);
if (rmap_count > RMAP_RECYCLE_THRESHOLD)
rmap_recycle(vcpu, sptep, gfn);
+ } else {
+ struct kvm_mmu_page *sp = page_header(__pa(sptep));
+ int index = sptep - sp->spt;
+
+ if (!sp->role.direct && sp->gfns[index] != gfn)
+ sp->gfns[index] = gfn;
}
kvm_release_pfn_clean(pfn);
if (speculative) {
next reply other threads:[~2011-01-25 13:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-25 13:07 Marcelo Tosatti [this message]
2011-01-25 14:32 ` KVM: MMU: update sp->gfns on pte update path Avi Kivity
2011-01-25 17:12 ` Marcelo Tosatti
2011-01-25 17:36 ` Avi Kivity
2011-01-31 13:54 ` Marcelo Tosatti
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=20110125130733.GA5645@amt.cnet \
--to=mtosatti@redhat.com \
--cc=avi@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=prochazka.nicolas@gmail.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox