[PATCH 1/3] KVM: nVMX: Really make emulated nested preemption timer pinned

Jim Mattson
2020-05-08T20:37:01Z

The PINNED bit is ignored by hrtimer_init. It is only considered when
starting the timer.

When the hrtimer isn't pinned to the same logical processor as the
vCPU thread to be interrupted, the emulated VMX-preemption timer
often fails to adhere to the architectural specification.

Fixes: f15a75eedc18e ("KVM: nVMX: make emulated nested preemption timer pinned")
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Oliver Upton <oupton@google.com>
---
arch/x86/kvm/vmx/nested.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index fd78ffbde644..1f7fe6f47cbc 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2041,7 +2041,7 @@ static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu)
preemption_timeout *= 1000000;
do_div(preemption_timeout, vcpu->arch.virtual_tsc_khz);
hrtimer_start(&vmx->nested.preemption_timer,
- ns_to_ktime(preemption_timeout), HRTIMER_MODE_REL);
+ ns_to_ktime(preemption_timeout), HRTIMER_MODE_REL_PINNED);
}

static u64 nested_vmx_calc_efer(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
--
2.26.2.645.ge9eca65c58-goog