As Marcelo pointed out, we need slots_lock to protect
against slots changing under our nose during wall clock
writing.
This patch address this issue.
Signed-off-by: Glauber Costa <[EMAIL PROTECTED]>
CC: Marcelo Tosatti <[EMAIL PROTECTED]>
---
arch/x86/kvm/x86.c | 10 ++++++----
1 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1ef56ad..9e4c6f2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -500,21 +500,21 @@ static void kvm_write_wall_clock(struct
if (!wall_clock)
return;
- mutex_lock(&kvm->lock);
-
version++;
+
+ down_read(&kvm->slots_lock);
kvm_write_guest(kvm, wall_clock, &version, sizeof(version));
wc_ts = current_kernel_time();
wc.wc_sec = wc_ts.tv_sec;
wc.wc_nsec = wc_ts.tv_nsec;
wc.wc_version = version;
+
kvm_write_guest(kvm, wall_clock, &wc, sizeof(wc));
version++;
kvm_write_guest(kvm, wall_clock, &version, sizeof(version));
-
- mutex_unlock(&kvm->lock);
+ up_read(&kvm->slots_lock);
}
static void kvm_write_guest_time(struct kvm_vcpu *v)
@@ -608,8 +608,10 @@ int kvm_set_msr_common(struct kvm_vcpu *
vcpu->arch.hv_clock.tsc_shift = 22;
down_read(¤t->mm->mmap_sem);
+ down_read(&vcpu->kvm->slots_lock);
vcpu->arch.time_page =
gfn_to_page(vcpu->kvm, data >> PAGE_SHIFT);
+ up_read(&vcpu->kvm->slots_lock);
up_read(¤t->mm->mmap_sem);
if (is_error_page(vcpu->arch.time_page)) {
--
1.4.2
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