* [PATCH v2 1/9] KVM: LAPIC: Return 0 when getting the tscdeadline timer if the lapic is hw disabled
2020-09-10 9:50 [PATCH v2 0/9] KVM: collect sporadic patches Wanpeng Li
@ 2020-09-10 9:50 ` Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 2/9] KVM: LAPIC: Guarantee the timer is in tsc-deadline mode when setting Wanpeng Li
` (8 subsequent siblings)
9 siblings, 0 replies; 13+ messages in thread
From: Wanpeng Li @ 2020-09-10 9:50 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel
From: Wanpeng Li <wanpengli@tencent.com>
Return 0 when getting the tscdeadline timer if the lapic is hw disabled.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/kvm/lapic.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 35cca2e..81bf6a8 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2183,8 +2183,7 @@ u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
- if (!lapic_in_kernel(vcpu) ||
- !apic_lvtt_tscdeadline(apic))
+ if (!kvm_apic_present(vcpu) || !apic_lvtt_tscdeadline(apic))
return 0;
return apic->lapic_timer.tscdeadline;
--
2.7.4
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH v2 2/9] KVM: LAPIC: Guarantee the timer is in tsc-deadline mode when setting
2020-09-10 9:50 [PATCH v2 0/9] KVM: collect sporadic patches Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 1/9] KVM: LAPIC: Return 0 when getting the tscdeadline timer if the lapic is hw disabled Wanpeng Li
@ 2020-09-10 9:50 ` Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 3/9] KVM: LAPIC: Fix updating DFR missing apic map recalculation Wanpeng Li
` (7 subsequent siblings)
9 siblings, 0 replies; 13+ messages in thread
From: Wanpeng Li @ 2020-09-10 9:50 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel
From: Wanpeng Li <wanpengli@tencent.com>
Check apic_lvtt_tscdeadline() mode directly instead of apic_lvtt_oneshot()
and apic_lvtt_period() to guarantee the timer is in tsc-deadline mode when
wrmsr MSR_IA32_TSCDEADLINE.
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/kvm/lapic.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 81bf6a8..33aab20 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2193,8 +2193,7 @@ void kvm_set_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu, u64 data)
{
struct kvm_lapic *apic = vcpu->arch.apic;
- if (!kvm_apic_present(vcpu) || apic_lvtt_oneshot(apic) ||
- apic_lvtt_period(apic))
+ if (!kvm_apic_present(vcpu) || !apic_lvtt_tscdeadline(apic))
return;
hrtimer_cancel(&apic->lapic_timer.timer);
--
2.7.4
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH v2 3/9] KVM: LAPIC: Fix updating DFR missing apic map recalculation
2020-09-10 9:50 [PATCH v2 0/9] KVM: collect sporadic patches Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 1/9] KVM: LAPIC: Return 0 when getting the tscdeadline timer if the lapic is hw disabled Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 2/9] KVM: LAPIC: Guarantee the timer is in tsc-deadline mode when setting Wanpeng Li
@ 2020-09-10 9:50 ` Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 4/9] KVM: VMX: Don't freeze guest when event delivery causes an APIC-access exit Wanpeng Li
` (6 subsequent siblings)
9 siblings, 0 replies; 13+ messages in thread
From: Wanpeng Li @ 2020-09-10 9:50 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel
From: Wanpeng Li <wanpengli@tencent.com>
There is missing apic map recalculation after updating DFR, if it is
INIT RESET, in x2apic mode, local apic is software enabled before.
This patch fix it by introducing the function kvm_apic_set_dfr() to
be called in INIT RESET handling path.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/kvm/lapic.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 33aab20..e446bdf 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -310,6 +310,12 @@ static inline void kvm_apic_set_ldr(struct kvm_lapic *apic, u32 id)
atomic_set_release(&apic->vcpu->kvm->arch.apic_map_dirty, DIRTY);
}
+static inline void kvm_apic_set_dfr(struct kvm_lapic *apic, u32 val)
+{
+ kvm_lapic_set_reg(apic, APIC_DFR, val);
+ atomic_set_release(&apic->vcpu->kvm->arch.apic_map_dirty, DIRTY);
+}
+
static inline u32 kvm_apic_calc_x2apic_ldr(u32 id)
{
return ((id >> 4) << 16) | (1 << (id & 0xf));
@@ -1984,10 +1990,9 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
break;
case APIC_DFR:
- if (!apic_x2apic_mode(apic)) {
- kvm_lapic_set_reg(apic, APIC_DFR, val | 0x0FFFFFFF);
- atomic_set_release(&apic->vcpu->kvm->arch.apic_map_dirty, DIRTY);
- } else
+ if (!apic_x2apic_mode(apic))
+ kvm_apic_set_dfr(apic, val | 0x0FFFFFFF);
+ else
ret = 1;
break;
@@ -2301,7 +2306,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT));
apic_manage_nmi_watchdog(apic, kvm_lapic_get_reg(apic, APIC_LVT0));
- kvm_lapic_set_reg(apic, APIC_DFR, 0xffffffffU);
+ kvm_apic_set_dfr(apic, 0xffffffffU);
apic_set_spiv(apic, 0xff);
kvm_lapic_set_reg(apic, APIC_TASKPRI, 0);
if (!apic_x2apic_mode(apic))
--
2.7.4
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH v2 4/9] KVM: VMX: Don't freeze guest when event delivery causes an APIC-access exit
2020-09-10 9:50 [PATCH v2 0/9] KVM: collect sporadic patches Wanpeng Li
` (2 preceding siblings ...)
2020-09-10 9:50 ` [PATCH v2 3/9] KVM: LAPIC: Fix updating DFR missing apic map recalculation Wanpeng Li
@ 2020-09-10 9:50 ` Wanpeng Li
2020-09-29 21:42 ` Jim Mattson
2020-09-10 9:50 ` [PATCH v2 5/9] KVM: LAPIC: Narrow down the kick target vCPU Wanpeng Li
` (5 subsequent siblings)
9 siblings, 1 reply; 13+ messages in thread
From: Wanpeng Li @ 2020-09-10 9:50 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel
From: Wanpeng Li <wanpengli@tencent.com>
According to SDM 27.2.4, Event delivery causes an APIC-access VM exit.
Don't report internal error and freeze guest when event delivery causes
an APIC-access exit, it is handleable and the event will be re-injected
during the next vmentry.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/kvm/vmx/vmx.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 819c185..a544351 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6054,6 +6054,7 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
(exit_reason != EXIT_REASON_EXCEPTION_NMI &&
exit_reason != EXIT_REASON_EPT_VIOLATION &&
exit_reason != EXIT_REASON_PML_FULL &&
+ exit_reason != EXIT_REASON_APIC_ACCESS &&
exit_reason != EXIT_REASON_TASK_SWITCH)) {
vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_DELIVERY_EV;
--
2.7.4
^ permalink raw reply related [flat|nested] 13+ messages in thread* Re: [PATCH v2 4/9] KVM: VMX: Don't freeze guest when event delivery causes an APIC-access exit
2020-09-10 9:50 ` [PATCH v2 4/9] KVM: VMX: Don't freeze guest when event delivery causes an APIC-access exit Wanpeng Li
@ 2020-09-29 21:42 ` Jim Mattson
0 siblings, 0 replies; 13+ messages in thread
From: Jim Mattson @ 2020-09-29 21:42 UTC (permalink / raw)
To: Wanpeng Li
Cc: LKML, kvm list, Paolo Bonzini, Sean Christopherson,
Vitaly Kuznetsov, Wanpeng Li, Joerg Roedel
On Thu, Sep 10, 2020 at 2:51 AM Wanpeng Li <kernellwp@gmail.com> wrote:
>
> From: Wanpeng Li <wanpengli@tencent.com>
>
> According to SDM 27.2.4, Event delivery causes an APIC-access VM exit.
> Don't report internal error and freeze guest when event delivery causes
> an APIC-access exit, it is handleable and the event will be re-injected
> during the next vmentry.
>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
I'm curious if you have a test case for this.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH v2 5/9] KVM: LAPIC: Narrow down the kick target vCPU
2020-09-10 9:50 [PATCH v2 0/9] KVM: collect sporadic patches Wanpeng Li
` (3 preceding siblings ...)
2020-09-10 9:50 ` [PATCH v2 4/9] KVM: VMX: Don't freeze guest when event delivery causes an APIC-access exit Wanpeng Li
@ 2020-09-10 9:50 ` Wanpeng Li
2020-09-12 6:46 ` Paolo Bonzini
2020-09-10 9:50 ` [PATCH v2 6/9] KVM: LAPIC: Reduce world switch latency caused by timer_advance_ns Wanpeng Li
` (4 subsequent siblings)
9 siblings, 1 reply; 13+ messages in thread
From: Wanpeng Li @ 2020-09-10 9:50 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel
From: Wanpeng Li <wanpengli@tencent.com>
The kick after setting KVM_REQ_PENDING_TIMER is used to handle the timer
fires on a different pCPU which vCPU is running on, this kick is expensive
since memory barrier, rcu, preemption disable/enable operations. We don't
need this kick when injecting already-expired timer, we also should call
out the VMX preemption timer case, which also passes from_timer_fn=false
but doesn't need a kick because kvm_lapic_expired_hv_timer() is called
from the target vCPU.
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/kvm/lapic.c | 4 +++-
arch/x86/kvm/x86.c | 6 ------
arch/x86/kvm/x86.h | 1 -
3 files changed, 3 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index e446bdf..3b32d3b 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1642,7 +1642,9 @@ static void apic_timer_expired(struct kvm_lapic *apic, bool from_timer_fn)
}
atomic_inc(&apic->lapic_timer.pending);
- kvm_set_pending_timer(vcpu);
+ kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
+ if (from_timer_fn)
+ kvm_vcpu_kick(vcpu);
}
static void start_sw_tscdeadline(struct kvm_lapic *apic)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d39d6cf..dcf4494 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1774,12 +1774,6 @@ static s64 get_kvmclock_base_ns(void)
}
#endif
-void kvm_set_pending_timer(struct kvm_vcpu *vcpu)
-{
- kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
- kvm_vcpu_kick(vcpu);
-}
-
static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
{
int version;
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 995ab69..ea20b8b 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -246,7 +246,6 @@ static inline bool kvm_vcpu_latch_init(struct kvm_vcpu *vcpu)
return is_smm(vcpu) || kvm_x86_ops.apic_init_signal_blocked(vcpu);
}
-void kvm_set_pending_timer(struct kvm_vcpu *vcpu);
void kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr);
--
2.7.4
^ permalink raw reply related [flat|nested] 13+ messages in thread* Re: [PATCH v2 5/9] KVM: LAPIC: Narrow down the kick target vCPU
2020-09-10 9:50 ` [PATCH v2 5/9] KVM: LAPIC: Narrow down the kick target vCPU Wanpeng Li
@ 2020-09-12 6:46 ` Paolo Bonzini
0 siblings, 0 replies; 13+ messages in thread
From: Paolo Bonzini @ 2020-09-12 6:46 UTC (permalink / raw)
To: Wanpeng Li, linux-kernel, kvm
Cc: Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
Joerg Roedel
On 10/09/20 11:50, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@tencent.com>
>
> The kick after setting KVM_REQ_PENDING_TIMER is used to handle the timer
> fires on a different pCPU which vCPU is running on, this kick is expensive
> since memory barrier, rcu, preemption disable/enable operations. We don't
> need this kick when injecting already-expired timer, we also should call
> out the VMX preemption timer case, which also passes from_timer_fn=false
> but doesn't need a kick because kvm_lapic_expired_hv_timer() is called
> from the target vCPU.
>
> Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> ---
> arch/x86/kvm/lapic.c | 4 +++-
> arch/x86/kvm/x86.c | 6 ------
> arch/x86/kvm/x86.h | 1 -
> 3 files changed, 3 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index e446bdf..3b32d3b 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -1642,7 +1642,9 @@ static void apic_timer_expired(struct kvm_lapic *apic, bool from_timer_fn)
> }
>
> atomic_inc(&apic->lapic_timer.pending);
> - kvm_set_pending_timer(vcpu);
> + kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
> + if (from_timer_fn)
> + kvm_vcpu_kick(vcpu);
> }
This only matters for !APICv, but it's nice anyway.
Paolo
> static void start_sw_tscdeadline(struct kvm_lapic *apic)
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index d39d6cf..dcf4494 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1774,12 +1774,6 @@ static s64 get_kvmclock_base_ns(void)
> }
> #endif
>
> -void kvm_set_pending_timer(struct kvm_vcpu *vcpu)
> -{
> - kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
> - kvm_vcpu_kick(vcpu);
> -}
> -
> static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
> {
> int version;
> diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
> index 995ab69..ea20b8b 100644
> --- a/arch/x86/kvm/x86.h
> +++ b/arch/x86/kvm/x86.h
> @@ -246,7 +246,6 @@ static inline bool kvm_vcpu_latch_init(struct kvm_vcpu *vcpu)
> return is_smm(vcpu) || kvm_x86_ops.apic_init_signal_blocked(vcpu);
> }
>
> -void kvm_set_pending_timer(struct kvm_vcpu *vcpu);
> void kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
>
> void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr);
>
^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH v2 6/9] KVM: LAPIC: Reduce world switch latency caused by timer_advance_ns
2020-09-10 9:50 [PATCH v2 0/9] KVM: collect sporadic patches Wanpeng Li
` (4 preceding siblings ...)
2020-09-10 9:50 ` [PATCH v2 5/9] KVM: LAPIC: Narrow down the kick target vCPU Wanpeng Li
@ 2020-09-10 9:50 ` Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 7/9] KVM: SVM: Get rid of handle_fastpath_set_msr_irqoff() Wanpeng Li
` (3 subsequent siblings)
9 siblings, 0 replies; 13+ messages in thread
From: Wanpeng Li @ 2020-09-10 9:50 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel
From: Wanpeng Li <wanpengli@tencent.com>
All the checks in lapic_timer_int_injected(), __kvm_wait_lapic_expire(), and
these function calls waste cpu cycles when the timer mode is not tscdeadline.
We can observe ~1.3% world switch time overhead by kvm-unit-tests/vmexit.flat
vmcall testing on AMD server. This patch reduces the world switch latency
caused by timer_advance_ns feature when the timer mode is not tscdeadline by
simpling move the check against apic->lapic_timer.expired_tscdeadline much
earlier.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/kvm/lapic.c | 11 +++++------
arch/x86/kvm/svm/svm.c | 4 +---
arch/x86/kvm/vmx/vmx.c | 4 +---
3 files changed, 7 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 3b32d3b..51ed4f0 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1582,9 +1582,6 @@ static void __kvm_wait_lapic_expire(struct kvm_vcpu *vcpu)
struct kvm_lapic *apic = vcpu->arch.apic;
u64 guest_tsc, tsc_deadline;
- if (apic->lapic_timer.expired_tscdeadline == 0)
- return;
-
tsc_deadline = apic->lapic_timer.expired_tscdeadline;
apic->lapic_timer.expired_tscdeadline = 0;
guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc());
@@ -1599,7 +1596,10 @@ static void __kvm_wait_lapic_expire(struct kvm_vcpu *vcpu)
void kvm_wait_lapic_expire(struct kvm_vcpu *vcpu)
{
- if (lapic_timer_int_injected(vcpu))
+ if (lapic_in_kernel(vcpu) &&
+ vcpu->arch.apic->lapic_timer.expired_tscdeadline &&
+ vcpu->arch.apic->lapic_timer.timer_advance_ns &&
+ lapic_timer_int_injected(vcpu))
__kvm_wait_lapic_expire(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_wait_lapic_expire);
@@ -1635,8 +1635,7 @@ static void apic_timer_expired(struct kvm_lapic *apic, bool from_timer_fn)
}
if (kvm_use_posted_timer_interrupt(apic->vcpu)) {
- if (apic->lapic_timer.timer_advance_ns)
- __kvm_wait_lapic_expire(vcpu);
+ kvm_wait_lapic_expire(vcpu);
kvm_apic_inject_pending_timer_irqs(apic);
return;
}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 0194336..19e622a 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3456,9 +3456,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
clgi();
kvm_load_guest_xsave_state(vcpu);
- if (lapic_in_kernel(vcpu) &&
- vcpu->arch.apic->lapic_timer.timer_advance_ns)
- kvm_wait_lapic_expire(vcpu);
+ kvm_wait_lapic_expire(vcpu);
/*
* If this vCPU has touched SPEC_CTRL, restore the guest's value if
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index a544351..d6e1656 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6800,9 +6800,7 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu)
if (enable_preemption_timer)
vmx_update_hv_timer(vcpu);
- if (lapic_in_kernel(vcpu) &&
- vcpu->arch.apic->lapic_timer.timer_advance_ns)
- kvm_wait_lapic_expire(vcpu);
+ kvm_wait_lapic_expire(vcpu);
/*
* If this vCPU has touched SPEC_CTRL, restore the guest's value if
--
2.7.4
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH v2 7/9] KVM: SVM: Get rid of handle_fastpath_set_msr_irqoff()
2020-09-10 9:50 [PATCH v2 0/9] KVM: collect sporadic patches Wanpeng Li
` (5 preceding siblings ...)
2020-09-10 9:50 ` [PATCH v2 6/9] KVM: LAPIC: Reduce world switch latency caused by timer_advance_ns Wanpeng Li
@ 2020-09-10 9:50 ` Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 8/9] KVM: SVM: Move svm_complete_interrupts() into svm_vcpu_run() Wanpeng Li
` (2 subsequent siblings)
9 siblings, 0 replies; 13+ messages in thread
From: Wanpeng Li @ 2020-09-10 9:50 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel, Paul K ., # v5 . 8-rc1+
From: Wanpeng Li <wanpengli@tencent.com>
Analysis from Sean:
| svm->next_rip is reset in svm_vcpu_run() only after calling
| svm_exit_handlers_fastpath(), which will cause SVM's
| skip_emulated_instruction() to write a stale RIP.
Let's get rid of handle_fastpath_set_msr_irqoff() in svm_exit_handlers_fastpath()
to have a quick fix.
Reported-by: Paul K. <kronenpj@kronenpj.dyndns.org>
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Paul K. <kronenpj@kronenpj.dyndns.org>
Cc: <stable@vger.kernel.org> # v5.8-rc1+
Fixes: 404d5d7bff0d (KVM: X86: Introduce more exit_fastpath_completion enum values)
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/kvm/svm/svm.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 19e622a..c61bc3b 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3349,11 +3349,6 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu)
static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
{
- if (!is_guest_mode(vcpu) &&
- to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR &&
- to_svm(vcpu)->vmcb->control.exit_info_1)
- return handle_fastpath_set_msr_irqoff(vcpu);
-
return EXIT_FASTPATH_NONE;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH v2 8/9] KVM: SVM: Move svm_complete_interrupts() into svm_vcpu_run()
2020-09-10 9:50 [PATCH v2 0/9] KVM: collect sporadic patches Wanpeng Li
` (6 preceding siblings ...)
2020-09-10 9:50 ` [PATCH v2 7/9] KVM: SVM: Get rid of handle_fastpath_set_msr_irqoff() Wanpeng Li
@ 2020-09-10 9:50 ` Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 9/9] KVM: SVM: Reenable handle_fastpath_set_msr_irqoff() after complete_interrupts() Wanpeng Li
2020-09-12 6:47 ` [PATCH v2 0/9] KVM: collect sporadic patches Paolo Bonzini
9 siblings, 0 replies; 13+ messages in thread
From: Wanpeng Li @ 2020-09-10 9:50 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel, Paul K .
From: Wanpeng Li <wanpengli@tencent.com>
Moving svm_complete_interrupts() into svm_vcpu_run() which can align VMX
and SVM with respect to completing interrupts.
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Paul K. <kronenpj@kronenpj.dyndns.org>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/kvm/svm/svm.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index c61bc3b..dafc14d 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2938,8 +2938,6 @@ static int handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
if (npt_enabled)
vcpu->arch.cr3 = svm->vmcb->save.cr3;
- svm_complete_interrupts(svm);
-
if (is_guest_mode(vcpu)) {
int vmexit;
@@ -3530,6 +3528,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
SVM_EXIT_EXCP_BASE + MC_VECTOR))
svm_handle_mce(svm);
+ svm_complete_interrupts(svm);
vmcb_mark_all_clean(svm->vmcb);
return exit_fastpath;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH v2 9/9] KVM: SVM: Reenable handle_fastpath_set_msr_irqoff() after complete_interrupts()
2020-09-10 9:50 [PATCH v2 0/9] KVM: collect sporadic patches Wanpeng Li
` (7 preceding siblings ...)
2020-09-10 9:50 ` [PATCH v2 8/9] KVM: SVM: Move svm_complete_interrupts() into svm_vcpu_run() Wanpeng Li
@ 2020-09-10 9:50 ` Wanpeng Li
2020-09-12 6:47 ` [PATCH v2 0/9] KVM: collect sporadic patches Paolo Bonzini
9 siblings, 0 replies; 13+ messages in thread
From: Wanpeng Li @ 2020-09-10 9:50 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel, Paul K .
From: Wanpeng Li <wanpengli@tencent.com>
Moving the call to svm_exit_handlers_fastpath() after svm_complete_interrupts()
since svm_complete_interrupts() consumes rip and reenable the function
handle_fastpath_set_msr_irqoff() call in svm_exit_handlers_fastpath().
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Paul K. <kronenpj@kronenpj.dyndns.org>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/kvm/svm/svm.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index dafc14d..b3e3429 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3347,6 +3347,10 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu)
static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
{
+ if (to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR &&
+ to_svm(vcpu)->vmcb->control.exit_info_1)
+ return handle_fastpath_set_msr_irqoff(vcpu);
+
return EXIT_FASTPATH_NONE;
}
@@ -3495,7 +3499,6 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
stgi();
/* Any pending NMI will happen here */
- exit_fastpath = svm_exit_handlers_fastpath(vcpu);
if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI))
kvm_after_interrupt(&svm->vcpu);
@@ -3530,6 +3533,12 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
svm_complete_interrupts(svm);
vmcb_mark_all_clean(svm->vmcb);
+
+ if (is_guest_mode(vcpu))
+ return EXIT_FASTPATH_NONE;
+
+ exit_fastpath = svm_exit_handlers_fastpath(vcpu);
+
return exit_fastpath;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 13+ messages in thread* Re: [PATCH v2 0/9] KVM: collect sporadic patches
2020-09-10 9:50 [PATCH v2 0/9] KVM: collect sporadic patches Wanpeng Li
` (8 preceding siblings ...)
2020-09-10 9:50 ` [PATCH v2 9/9] KVM: SVM: Reenable handle_fastpath_set_msr_irqoff() after complete_interrupts() Wanpeng Li
@ 2020-09-12 6:47 ` Paolo Bonzini
9 siblings, 0 replies; 13+ messages in thread
From: Paolo Bonzini @ 2020-09-12 6:47 UTC (permalink / raw)
To: Wanpeng Li, linux-kernel, kvm
Cc: Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
Joerg Roedel
On 10/09/20 11:50, Wanpeng Li wrote:
> Collect sporadic patches for easy apply.
>
> Wanpeng Li (9):
> KVM: LAPIC: Return 0 when getting the tscdeadline timer if the lapic
> is hw disabled
> KVM: LAPIC: Guarantee the timer is in tsc-deadline mode when setting
> KVM: LAPIC: Fix updating DFR missing apic map recalculation
> KVM: VMX: Don't freeze guest when event delivery causes an APIC-access
> exit
> KVM: LAPIC: Narrow down the kick target vCPU
> KVM: LAPIC: Reduce world switch latency caused by timer_advance_ns
> KVM: SVM: Get rid of handle_fastpath_set_msr_irqoff()
> KVM: SVM: Move svm_complete_interrupts() into svm_vcpu_run()
> KVM: SVM: Reenable handle_fastpath_set_msr_irqoff() after
> complete_interrupts()
>
> arch/x86/kvm/lapic.c | 36 ++++++++++++++++++++----------------
> arch/x86/kvm/svm/svm.c | 17 +++++++++--------
> arch/x86/kvm/vmx/vmx.c | 5 ++---
> arch/x86/kvm/x86.c | 6 ------
> arch/x86/kvm/x86.h | 1 -
> 5 files changed, 31 insertions(+), 34 deletions(-)
>
Queued what was left, thanks.
Paolo
^ permalink raw reply [flat|nested] 13+ messages in thread