| Date | Tue, 04 Jun 2013 19:22:26 +0200 | From | Willy Tarreau <> | Subject | [ 056/184] KVM: x86: relax MSR_KVM_SYSTEM_TIME alignment check |
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2.6.32-longterm review patch. If anyone has any objections, please let me know.
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From: Marcelo Tosatti <mtosatti@redhat.com>
RHEL5 i386 guests register non 32-byte aligned addresses:
kvm-clock: cpu 1, msr 0:3018aa5, secondary cpu clock kvm-clock: cpu 2, msr 0:301f8e9, secondary cpu clock kvm-clock: cpu 3, msr 0:302672d, secondary cpu clock
Check for an address+len that would cross page boundary instead.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> [dannf: backported to Debian's 2.6.32] Signed-off-by: Willy Tarreau <w@1wt.eu> --- arch/x86/kvm/x86.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e24e9ce..79905f2 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -925,9 +925,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) /* ...but clean it before doing the actual write */ vcpu->arch.time_offset = data & ~(PAGE_MASK | 1); - /* Check that the address is 32-byte aligned. */ - if (vcpu->arch.time_offset & - (sizeof(struct pvclock_vcpu_time_info) - 1)) + /* Check that address+len does not cross page boundary */ + if ((vcpu->arch.time_offset + + sizeof(struct pvclock_vcpu_time_info) - 1) + & PAGE_MASK) break; vcpu->arch.time_page = -- 1.7.12.2.21.g234cd45.dirty
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