This is a note to let you know that I've just added the patch titled
Revert "KVM: x86: fix missed hardware breakpoints"
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
revert-kvm-x86-fix-missed-hardware-breakpoints.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From pbonzini@xxxxxxxxxx Tue Sep 20 14:08:11 2016
From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Date: Thu, 15 Sep 2016 23:52:43 +0200
Subject: Revert "KVM: x86: fix missed hardware breakpoints"
To: stable@xxxxxxxxxxxxxxx
Cc: matt@xxxxxxxxxxxxxxxxxxx, Paolo Bonzini <pbonzini@xxxxxxxxxx>
Message-ID: <1473976363-22653-1-git-send-email-pbonzini@xxxxxxxxxx>
From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
[the change is part of 70e4da7a8ff62f2775337b705f45c804bb450454, which
is already in stable kernels 4.1.y to 4.4.y. this part of the fix
however was later undone, so remove the line again]
The following patches were applied in the wrong order in -stable. This
is the order as they appear in Linus' tree,
[0] commit 4e422bdd2f84 ("KVM: x86: fix missed hardware breakpoints")
[1] commit 172b2386ed16 ("KVM: x86: fix missed hardware breakpoints")
[2] commit 70e4da7a8ff6 ("KVM: x86: fix root cause for missed hardware breakpoints")
but this is the order for linux-4.4.y
[1] commit fc90441e728a ("KVM: x86: fix missed hardware breakpoints")
[2] commit 25e8618619a5 ("KVM: x86: fix root cause for missed hardware breakpoints")
[0] commit 0f6e5e26e68f ("KVM: x86: fix missed hardware breakpoints")
The upshot is that KVM_DEBUGREG_RELOAD is always set when returning
from kvm_arch_vcpu_load() in stable, but not in Linus' tree.
This happened because [0] and [1] are the same patch. [0] and [1] come from two
different merges, and the later merge is trivially resolved; when [2]
is applied it reverts both of them. Instead, when using the [1][2][0]
order, patches applies normally but "KVM: x86: fix missed hardware
breakpoints" is present in the final tree.
Reported-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 1 -
1 file changed, 1 deletion(-)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2735,7 +2735,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu
}
kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);
- vcpu->arch.switch_db_regs |= KVM_DEBUGREG_RELOAD;
}
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
Patches currently in stable-queue which might be from pbonzini@xxxxxxxxxx are
queue-4.4/mips-kvm-check-for-pfn-noslot-case.patch
queue-4.4/revert-kvm-x86-fix-missed-hardware-breakpoints.patch
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