From: Wanpeng Li <[email protected]>
Prevent setting the tscdeadline timer if the lapic is hw disabled.
Fixes: bce87cce88 (KVM: x86: consolidate different ways to test for in-kernel LAPIC)
Cc: <[email protected]>
Signed-off-by: Wanpeng Li <[email protected]>
---
arch/x86/kvm/lapic.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 5bf72fc..4ce2ddd 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2195,7 +2195,7 @@ void kvm_set_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu, u64 data)
{
struct kvm_lapic *apic = vcpu->arch.apic;
- if (!lapic_in_kernel(vcpu) || apic_lvtt_oneshot(apic) ||
+ if (!kvm_apic_present(vcpu) || apic_lvtt_oneshot(apic) ||
apic_lvtt_period(apic))
return;
--
2.7.4
From: Wanpeng Li <[email protected]>
It is a little different between Intel and AMD, Intel's bit 2
is 0 and AMD is reserved. On bare-metal, Intel will refuse to set
APIC_TDCR once bits except 0, 1, 3 are setting, however, AMD will
accept bits 0, 1, 3 and ignore other bits setting as patch does.
Before the patch, we can get back anything what we set to the
APIC_TDCR, this patch improves it.
Signed-off-by: Wanpeng Li <[email protected]>
---
arch/x86/kvm/lapic.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 4ce2ddd..8f7a14d 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2068,7 +2068,7 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
case APIC_TDCR: {
uint32_t old_divisor = apic->divide_count;
- kvm_lapic_set_reg(apic, APIC_TDCR, val);
+ kvm_lapic_set_reg(apic, APIC_TDCR, val & 0xb);
update_divide_count(apic);
if (apic->divide_count != old_divisor &&
apic->lapic_timer.period) {
--
2.7.4
From: Wanpeng Li <[email protected]>
Commit 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM) drops
disable pause loop exit/pause filtering capability completely, I guess it
is a merge fault by Radim since disable vmexits capabilities and pause
loop exit for SVM patchsets are merged at the same time. This patch
reintroduces the disable pause loop exit/pause filtering capability
support.
We can observe 2.9% hackbench improvement for a 92 vCPUs guest on AMD
Rome Server.
Reported-by: Haiwei Li <[email protected]>
Tested-by: Haiwei Li <[email protected]>
Fixes: 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM)
Signed-off-by: Wanpeng Li <[email protected]>
---
arch/x86/kvm/svm/svm.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index c0da4dd..c20f127 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1090,7 +1090,7 @@ static void init_vmcb(struct vcpu_svm *svm)
svm->nested.vmcb = 0;
svm->vcpu.arch.hflags = 0;
- if (pause_filter_count) {
+ if (pause_filter_count && !kvm_pause_in_guest(svm->vcpu.kvm)) {
control->pause_filter_count = pause_filter_count;
if (pause_filter_thresh)
control->pause_filter_thresh = pause_filter_thresh;
@@ -2693,7 +2693,7 @@ static int pause_interception(struct vcpu_svm *svm)
struct kvm_vcpu *vcpu = &svm->vcpu;
bool in_kernel = (svm_get_cpl(vcpu) == 0);
- if (pause_filter_thresh)
+ if (!kvm_pause_in_guest(vcpu->kvm))
grow_ple_window(vcpu);
kvm_vcpu_on_spin(vcpu, in_kernel);
@@ -3780,7 +3780,7 @@ static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu)
static void svm_sched_in(struct kvm_vcpu *vcpu, int cpu)
{
- if (pause_filter_thresh)
+ if (!kvm_pause_in_guest(vcpu->kvm))
shrink_ple_window(vcpu);
}
@@ -3958,6 +3958,9 @@ static void svm_vm_destroy(struct kvm *kvm)
static int svm_vm_init(struct kvm *kvm)
{
+ if (!pause_filter_thresh)
+ kvm->arch.pause_in_guest = true;
+
if (avic) {
int ret = avic_vm_init(kvm);
if (ret)
--
2.7.4
Wanpeng Li <[email protected]> writes:
> From: Wanpeng Li <[email protected]>
>
> Commit 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM) drops
> disable pause loop exit/pause filtering capability completely, I guess it
> is a merge fault by Radim since disable vmexits capabilities and pause
> loop exit for SVM patchsets are merged at the same time. This patch
> reintroduces the disable pause loop exit/pause filtering capability
> support.
>
> We can observe 2.9% hackbench improvement for a 92 vCPUs guest on AMD
> Rome Server.
>
> Reported-by: Haiwei Li <[email protected]>
> Tested-by: Haiwei Li <[email protected]>
> Fixes: 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM)
> Signed-off-by: Wanpeng Li <[email protected]>
> ---
> arch/x86/kvm/svm/svm.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index c0da4dd..c20f127 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -1090,7 +1090,7 @@ static void init_vmcb(struct vcpu_svm *svm)
> svm->nested.vmcb = 0;
> svm->vcpu.arch.hflags = 0;
>
> - if (pause_filter_count) {
> + if (pause_filter_count && !kvm_pause_in_guest(svm->vcpu.kvm)) {
> control->pause_filter_count = pause_filter_count;
> if (pause_filter_thresh)
> control->pause_filter_thresh = pause_filter_thresh;
> @@ -2693,7 +2693,7 @@ static int pause_interception(struct vcpu_svm *svm)
> struct kvm_vcpu *vcpu = &svm->vcpu;
> bool in_kernel = (svm_get_cpl(vcpu) == 0);
>
> - if (pause_filter_thresh)
> + if (!kvm_pause_in_guest(vcpu->kvm))
> grow_ple_window(vcpu);
>
> kvm_vcpu_on_spin(vcpu, in_kernel);
> @@ -3780,7 +3780,7 @@ static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu)
>
> static void svm_sched_in(struct kvm_vcpu *vcpu, int cpu)
> {
> - if (pause_filter_thresh)
> + if (!kvm_pause_in_guest(vcpu->kvm))
> shrink_ple_window(vcpu);
> }
>
> @@ -3958,6 +3958,9 @@ static void svm_vm_destroy(struct kvm *kvm)
>
> static int svm_vm_init(struct kvm *kvm)
> {
> + if (!pause_filter_thresh)
> + kvm->arch.pause_in_guest = true;
Would it make sense to do
if (!pause_filter_count || !pause_filter_thresh)
kvm->arch.pause_in_guest = true;
here and simplify the condition in init_vmcb()?
> +
> if (avic) {
> int ret = avic_vm_init(kvm);
> if (ret)
--
Vitaly
On Wed, 29 Jul 2020 at 20:21, Vitaly Kuznetsov <[email protected]> wrote:
>
> Wanpeng Li <[email protected]> writes:
>
> > From: Wanpeng Li <[email protected]>
> >
> > Commit 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM) drops
> > disable pause loop exit/pause filtering capability completely, I guess it
> > is a merge fault by Radim since disable vmexits capabilities and pause
> > loop exit for SVM patchsets are merged at the same time. This patch
> > reintroduces the disable pause loop exit/pause filtering capability
> > support.
> >
> > We can observe 2.9% hackbench improvement for a 92 vCPUs guest on AMD
> > Rome Server.
> >
> > Reported-by: Haiwei Li <[email protected]>
> > Tested-by: Haiwei Li <[email protected]>
> > Fixes: 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM)
> > Signed-off-by: Wanpeng Li <[email protected]>
> > ---
> > arch/x86/kvm/svm/svm.c | 9 ++++++---
> > 1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> > index c0da4dd..c20f127 100644
> > --- a/arch/x86/kvm/svm/svm.c
> > +++ b/arch/x86/kvm/svm/svm.c
> > @@ -1090,7 +1090,7 @@ static void init_vmcb(struct vcpu_svm *svm)
> > svm->nested.vmcb = 0;
> > svm->vcpu.arch.hflags = 0;
> >
> > - if (pause_filter_count) {
> > + if (pause_filter_count && !kvm_pause_in_guest(svm->vcpu.kvm)) {
> > control->pause_filter_count = pause_filter_count;
> > if (pause_filter_thresh)
> > control->pause_filter_thresh = pause_filter_thresh;
> > @@ -2693,7 +2693,7 @@ static int pause_interception(struct vcpu_svm *svm)
> > struct kvm_vcpu *vcpu = &svm->vcpu;
> > bool in_kernel = (svm_get_cpl(vcpu) == 0);
> >
> > - if (pause_filter_thresh)
> > + if (!kvm_pause_in_guest(vcpu->kvm))
> > grow_ple_window(vcpu);
> >
> > kvm_vcpu_on_spin(vcpu, in_kernel);
> > @@ -3780,7 +3780,7 @@ static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu)
> >
> > static void svm_sched_in(struct kvm_vcpu *vcpu, int cpu)
> > {
> > - if (pause_filter_thresh)
> > + if (!kvm_pause_in_guest(vcpu->kvm))
> > shrink_ple_window(vcpu);
> > }
> >
> > @@ -3958,6 +3958,9 @@ static void svm_vm_destroy(struct kvm *kvm)
> >
> > static int svm_vm_init(struct kvm *kvm)
> > {
> > + if (!pause_filter_thresh)
> > + kvm->arch.pause_in_guest = true;
>
> Would it make sense to do
>
> if (!pause_filter_count || !pause_filter_thresh)
> kvm->arch.pause_in_guest = true;
>
> here and simplify the condition in init_vmcb()?
kvm->arch.pause_in_guest can also be true when userspace sets the
KVM_CAP_X86_DISABLE_EXITS capability, so we can't simplify the
condition in init_vmcb().
Wanpeng
Wanpeng Li <[email protected]> writes:
> On Wed, 29 Jul 2020 at 20:21, Vitaly Kuznetsov <[email protected]> wrote:
>>
>> Wanpeng Li <[email protected]> writes:
>>
>> > From: Wanpeng Li <[email protected]>
>> >
>> > Commit 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM) drops
>> > disable pause loop exit/pause filtering capability completely, I guess it
>> > is a merge fault by Radim since disable vmexits capabilities and pause
>> > loop exit for SVM patchsets are merged at the same time. This patch
>> > reintroduces the disable pause loop exit/pause filtering capability
>> > support.
>> >
>> > We can observe 2.9% hackbench improvement for a 92 vCPUs guest on AMD
>> > Rome Server.
>> >
>> > Reported-by: Haiwei Li <[email protected]>
>> > Tested-by: Haiwei Li <[email protected]>
>> > Fixes: 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM)
>> > Signed-off-by: Wanpeng Li <[email protected]>
>> > ---
>> > arch/x86/kvm/svm/svm.c | 9 ++++++---
>> > 1 file changed, 6 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
>> > index c0da4dd..c20f127 100644
>> > --- a/arch/x86/kvm/svm/svm.c
>> > +++ b/arch/x86/kvm/svm/svm.c
>> > @@ -1090,7 +1090,7 @@ static void init_vmcb(struct vcpu_svm *svm)
>> > svm->nested.vmcb = 0;
>> > svm->vcpu.arch.hflags = 0;
>> >
>> > - if (pause_filter_count) {
>> > + if (pause_filter_count && !kvm_pause_in_guest(svm->vcpu.kvm)) {
>> > control->pause_filter_count = pause_filter_count;
>> > if (pause_filter_thresh)
>> > control->pause_filter_thresh = pause_filter_thresh;
>> > @@ -2693,7 +2693,7 @@ static int pause_interception(struct vcpu_svm *svm)
>> > struct kvm_vcpu *vcpu = &svm->vcpu;
>> > bool in_kernel = (svm_get_cpl(vcpu) == 0);
>> >
>> > - if (pause_filter_thresh)
>> > + if (!kvm_pause_in_guest(vcpu->kvm))
>> > grow_ple_window(vcpu);
>> >
>> > kvm_vcpu_on_spin(vcpu, in_kernel);
>> > @@ -3780,7 +3780,7 @@ static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu)
>> >
>> > static void svm_sched_in(struct kvm_vcpu *vcpu, int cpu)
>> > {
>> > - if (pause_filter_thresh)
>> > + if (!kvm_pause_in_guest(vcpu->kvm))
>> > shrink_ple_window(vcpu);
>> > }
>> >
>> > @@ -3958,6 +3958,9 @@ static void svm_vm_destroy(struct kvm *kvm)
>> >
>> > static int svm_vm_init(struct kvm *kvm)
>> > {
>> > + if (!pause_filter_thresh)
>> > + kvm->arch.pause_in_guest = true;
>>
>> Would it make sense to do
>>
>> if (!pause_filter_count || !pause_filter_thresh)
>> kvm->arch.pause_in_guest = true;
>>
>> here and simplify the condition in init_vmcb()?
>
> kvm->arch.pause_in_guest can also be true when userspace sets the
> KVM_CAP_X86_DISABLE_EXITS capability, so we can't simplify the
> condition in init_vmcb().
>
I meant we simplify it to
if (!kvm_pause_in_guest(svm->vcpu.kvm))
as "!pause_filter_count" gets included.
--
Vitaly
On Thu, 30 Jul 2020 at 19:16, Vitaly Kuznetsov <[email protected]> wrote:
>
> Wanpeng Li <[email protected]> writes:
>
> > On Wed, 29 Jul 2020 at 20:21, Vitaly Kuznetsov <[email protected]> wrote:
> >>
> >> Wanpeng Li <[email protected]> writes:
> >>
> >> > From: Wanpeng Li <[email protected]>
> >> >
> >> > Commit 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM) drops
> >> > disable pause loop exit/pause filtering capability completely, I guess it
> >> > is a merge fault by Radim since disable vmexits capabilities and pause
> >> > loop exit for SVM patchsets are merged at the same time. This patch
> >> > reintroduces the disable pause loop exit/pause filtering capability
> >> > support.
> >> >
> >> > We can observe 2.9% hackbench improvement for a 92 vCPUs guest on AMD
> >> > Rome Server.
> >> >
> >> > Reported-by: Haiwei Li <[email protected]>
> >> > Tested-by: Haiwei Li <[email protected]>
> >> > Fixes: 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM)
> >> > Signed-off-by: Wanpeng Li <[email protected]>
> >> > ---
> >> > arch/x86/kvm/svm/svm.c | 9 ++++++---
> >> > 1 file changed, 6 insertions(+), 3 deletions(-)
> >> >
> >> > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> >> > index c0da4dd..c20f127 100644
> >> > --- a/arch/x86/kvm/svm/svm.c
> >> > +++ b/arch/x86/kvm/svm/svm.c
> >> > @@ -1090,7 +1090,7 @@ static void init_vmcb(struct vcpu_svm *svm)
> >> > svm->nested.vmcb = 0;
> >> > svm->vcpu.arch.hflags = 0;
> >> >
> >> > - if (pause_filter_count) {
> >> > + if (pause_filter_count && !kvm_pause_in_guest(svm->vcpu.kvm)) {
> >> > control->pause_filter_count = pause_filter_count;
> >> > if (pause_filter_thresh)
> >> > control->pause_filter_thresh = pause_filter_thresh;
> >> > @@ -2693,7 +2693,7 @@ static int pause_interception(struct vcpu_svm *svm)
> >> > struct kvm_vcpu *vcpu = &svm->vcpu;
> >> > bool in_kernel = (svm_get_cpl(vcpu) == 0);
> >> >
> >> > - if (pause_filter_thresh)
> >> > + if (!kvm_pause_in_guest(vcpu->kvm))
> >> > grow_ple_window(vcpu);
> >> >
> >> > kvm_vcpu_on_spin(vcpu, in_kernel);
> >> > @@ -3780,7 +3780,7 @@ static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu)
> >> >
> >> > static void svm_sched_in(struct kvm_vcpu *vcpu, int cpu)
> >> > {
> >> > - if (pause_filter_thresh)
> >> > + if (!kvm_pause_in_guest(vcpu->kvm))
> >> > shrink_ple_window(vcpu);
> >> > }
> >> >
> >> > @@ -3958,6 +3958,9 @@ static void svm_vm_destroy(struct kvm *kvm)
> >> >
> >> > static int svm_vm_init(struct kvm *kvm)
> >> > {
> >> > + if (!pause_filter_thresh)
> >> > + kvm->arch.pause_in_guest = true;
> >>
> >> Would it make sense to do
> >>
> >> if (!pause_filter_count || !pause_filter_thresh)
> >> kvm->arch.pause_in_guest = true;
> >>
> >> here and simplify the condition in init_vmcb()?
> >
> > kvm->arch.pause_in_guest can also be true when userspace sets the
> > KVM_CAP_X86_DISABLE_EXITS capability, so we can't simplify the
> > condition in init_vmcb().
> >
>
> I meant we simplify it to
>
> if (!kvm_pause_in_guest(svm->vcpu.kvm))
>
> as "!pause_filter_count" gets included.
Just do it in v3.
Wanpeng