Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1587903 > unrolled thread

[PATCH v2 2/5] KVM: add KVM request variants without barrier

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  [PATCH v2 2/5] KVM: add KVM request variants without barrier Radim Krčmář <rkrcmar@redhat.com> - 2017-02-24 21:00 +0100
    Re: [PATCH v2 2/5] KVM: add KVM request variants without barrier David Hildenbrand <david@redhat.com> - 2017-02-27 11:10 +0100
      Re: [PATCH v2 2/5] KVM: add KVM request variants without barrier David Hildenbrand <david@redhat.com> - 2017-02-27 11:30 +0100
    Re: [PATCH v2 2/5] KVM: add KVM request variants without barrier Peter Xu <peterx@redhat.com> - 2017-02-28 08:40 +0100
      Re: [PATCH v2 2/5] KVM: add KVM request variants without barrier Peter Xu <peterx@redhat.com> - 2017-02-28 08:50 +0100

#1587903 — [PATCH v2 2/5] KVM: add KVM request variants without barrier

The leading underscores denote that the call is just a bitop wrapper.

Switch all users of open-coded set/check/test to kvm_request ones.

Automated by coccinelle script:
  @@
  expression VCPU, REQ;
  @@
  -set_bit(REQ, &VCPU->requests)
  +__kvm_request_set(REQ, VCPU)

  @@
  expression VCPU, REQ;
  @@
  -clear_bit(REQ, &VCPU->requests)
  +__kvm_request_clear(REQ, VCPU)

  @@
  expression VCPU, REQ;
  @@
  -test_bit(REQ, &VCPU->requests)
  +__kvm_request_test(REQ, VCPU)

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 v2: clear_bit in __kvm_request_clear [Paolo]
---
 arch/mips/kvm/emulate.c           |  2 +-
 arch/powerpc/kvm/book3s_pr.c      |  2 +-
 arch/powerpc/kvm/book3s_pr_papr.c |  2 +-
 arch/powerpc/kvm/booke.c          |  4 ++--
 arch/powerpc/kvm/powerpc.c        |  2 +-
 arch/s390/kvm/kvm-s390.c          |  2 +-
 arch/x86/kvm/vmx.c                |  2 +-
 arch/x86/kvm/x86.c                | 14 +++++++-------
 include/linux/kvm_host.h          | 23 ++++++++++++++++++++---
 9 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index ee4af898bcf6..552ae2b5e911 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -865,7 +865,7 @@ enum emulation_result kvm_mips_emul_wait(struct kvm_vcpu *vcpu)
 		 * check if any I/O interrupts are pending.
 		 */
 		if (kvm_request_test_and_clear(KVM_REQ_UNHALT, vcpu)) {
-			clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
+			__kvm_request_clear(KVM_REQ_UNHALT, vcpu);
 			vcpu->run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
 		}
 	}
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 7af5154e848b..f5894d27a8a9 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -349,7 +349,7 @@ static void kvmppc_set_msr_pr(struct kvm_vcpu *vcpu, u64 msr)
 	if (msr & MSR_POW) {
 		if (!vcpu->arch.pending_exceptions) {
 			kvm_vcpu_block(vcpu);
-			clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
+			__kvm_request_clear(KVM_REQ_UNHALT, vcpu);
 			vcpu->stat.halt_wakeup++;
 
 			/* Unset POW bit after we woke up */
diff --git a/arch/powerpc/kvm/book3s_pr_papr.c b/arch/powerpc/kvm/book3s_pr_papr.c
index f102616febc7..86847220811a 100644
--- a/arch/powerpc/kvm/book3s_pr_papr.c
+++ b/arch/powerpc/kvm/book3s_pr_papr.c
@@ -344,7 +344,7 @@ int kvmppc_h_pr(struct kvm_vcpu *vcpu, unsigned long cmd)
 	case H_CEDE:
 		kvmppc_set_msr_fast(vcpu, kvmppc_get_msr(vcpu) | MSR_EE);
 		kvm_vcpu_block(vcpu);
-		clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
+		__kvm_request_clear(KVM_REQ_UNHALT, vcpu);
 		vcpu->stat.halt_wakeup++;
 		return EMULATE_DONE;
 	case H_LOGICAL_CI_LOAD:
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 806caaf60e10..e9098af0ab2a 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -579,7 +579,7 @@ static void arm_next_watchdog(struct kvm_vcpu *vcpu)
 	 * userspace, so clear the KVM_REQ_WATCHDOG request.
 	 */
 	if ((vcpu->arch.tsr & (TSR_ENW | TSR_WIS)) != (TSR_ENW | TSR_WIS))
-		clear_bit(KVM_REQ_WATCHDOG, &vcpu->requests);
+		__kvm_request_clear(KVM_REQ_WATCHDOG, vcpu);
 
 	spin_lock_irqsave(&vcpu->arch.wdt_lock, flags);
 	nr_jiffies = watchdog_next_timeout(vcpu);
@@ -690,7 +690,7 @@ int kvmppc_core_prepare_to_enter(struct kvm_vcpu *vcpu)
 	if (vcpu->arch.shared->msr & MSR_WE) {
 		local_irq_enable();
 		kvm_vcpu_block(vcpu);
-		clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
+		__kvm_request_clear(KVM_REQ_UNHALT, vcpu);
 		hard_irq_disable();
 
 		kvmppc_set_exit_type(vcpu, EMULATED_MTMSRWE_EXITS);
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 03f563000160..2bcc03548c03 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -231,7 +231,7 @@ int kvmppc_kvm_pv(struct kvm_vcpu *vcpu)
 	case EV_HCALL_TOKEN(EV_IDLE):
 		r = EV_SUCCESS;
 		kvm_vcpu_block(vcpu);
-		clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
+		__kvm_request_clear(KVM_REQ_UNHALT, vcpu);
 		break;
 	default:
 		r = EV_UNIMPLEMENTED;
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 8fb210974c42..b10acac8facf 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2444,7 +2444,7 @@ static int kvm_s390_handle_requests(struct kvm_vcpu *vcpu)
 	}
 
 	/* nothing to do, just clear the request */
-	clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
+	__kvm_request_clear(KVM_REQ_UNHALT, vcpu);
 
 	return 0;
 }
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 398d2d5f6d5c..4b005beaaa8e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6343,7 +6343,7 @@ static int handle_invalid_guest_state(struct kvm_vcpu *vcpu)
 		if (intr_window_requested && vmx_interrupt_allowed(vcpu))
 			return handle_interrupt_window(&vmx->vcpu);
 
-		if (test_bit(KVM_REQ_EVENT, &vcpu->requests))
+		if (__kvm_request_test(KVM_REQ_EVENT, vcpu))
 			return 1;
 
 		err = emulate_instruction(vcpu, EMULTYPE_NO_REEXECUTE);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3ceb1339ed86..16493795ab21 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1767,7 +1767,7 @@ static void kvm_gen_update_masterclock(struct kvm *kvm)
 
 	/* guest entries allowed */
 	kvm_for_each_vcpu(i, vcpu, kvm)
-		clear_bit(KVM_REQ_MCLOCK_INPROGRESS, &vcpu->requests);
+		__kvm_request_clear(KVM_REQ_MCLOCK_INPROGRESS, vcpu);
 
 	spin_unlock(&ka->pvclock_gtod_sync_lock);
 #endif
@@ -2228,8 +2228,8 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			bool tmp = (msr == MSR_KVM_SYSTEM_TIME);
 
 			if (ka->boot_vcpu_runs_old_kvmclock != tmp)
-				set_bit(KVM_REQ_MASTERCLOCK_UPDATE,
-					&vcpu->requests);
+				__kvm_request_set(KVM_REQ_MASTERCLOCK_UPDATE,
+						  vcpu);
 
 			ka->boot_vcpu_runs_old_kvmclock = tmp;
 		}
@@ -2816,7 +2816,7 @@ static bool need_emulate_wbinvd(struct kvm_vcpu *vcpu)
 
 static inline void kvm_migrate_timers(struct kvm_vcpu *vcpu)
 {
-	set_bit(KVM_REQ_MIGRATE_TIMER, &vcpu->requests);
+	__kvm_request_set(KVM_REQ_MIGRATE_TIMER, vcpu);
 }
 
 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
@@ -7049,7 +7049,7 @@ static int vcpu_run(struct kvm_vcpu *vcpu)
 		if (r <= 0)
 			break;
 
-		clear_bit(KVM_REQ_PENDING_TIMER, &vcpu->requests);
+		__kvm_request_clear(KVM_REQ_PENDING_TIMER, vcpu);
 		if (kvm_cpu_has_pending_timer(vcpu))
 			kvm_inject_pending_timer_irqs(vcpu);
 
@@ -7177,7 +7177,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_UNINITIALIZED)) {
 		kvm_vcpu_block(vcpu);
 		kvm_apic_accept_events(vcpu);
-		clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
+		__kvm_request_clear(KVM_REQ_UNHALT, vcpu);
 		r = -EAGAIN;
 		goto out;
 	}
@@ -8382,7 +8382,7 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
 	if (atomic_read(&vcpu->arch.nmi_queued))
 		return true;
 
-	if (test_bit(KVM_REQ_SMI, &vcpu->requests))
+	if (__kvm_request_test(KVM_REQ_SMI, vcpu))
 		return true;
 
 	if (kvm_arch_interrupt_allowed(vcpu) &&
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 4cf61ee84b2e..6d637dbbb82f 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1099,10 +1099,17 @@ static inline int kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
  *
  * TODO:
  *  - completely encapsulate vcpu->requests
+ *  - do not use __kvm_request* outside request helpers
  *  - do not use memory barrier in (1) and (2)
  *  - let architectures define custom vcpu kick
  *  - add kick when setting remote request
  */
+
+static inline void __kvm_request_set(unsigned req, struct kvm_vcpu *vcpu)
+{
+	set_bit(req, &vcpu->requests);
+}
+
 static inline void kvm_request_set(unsigned req, struct kvm_vcpu *vcpu)
 {
 	/*
@@ -1111,13 +1118,23 @@ static inline void kvm_request_set(unsigned req, struct kvm_vcpu *vcpu)
 	 * Paired with the smp_mb__after_atomic in kvm_request_test_and_clear.
 	 */
 	smp_wmb();
-	set_bit(req, &vcpu->requests);
+	__kvm_request_set(req, vcpu);
+}
+
+static inline bool __kvm_request_test(unsigned req, struct kvm_vcpu *vcpu)
+{
+	return test_bit(req, &vcpu->requests);
+}
+
+static inline void __kvm_request_clear(unsigned req, struct kvm_vcpu *vcpu)
+{
+	clear_bit(req, &vcpu->requests);
 }
 
 static inline bool kvm_request_test_and_clear(unsigned req, struct kvm_vcpu *vcpu)
 {
-	if (test_bit(req, &vcpu->requests)) {
-		clear_bit(req, &vcpu->requests);
+	if (__kvm_request_test(req, vcpu)) {
+		__kvm_request_clear(req, vcpu);
 
 		/*
 		 * Ensure the rest of the request is visible to
-- 
2.11.1

[toc] | [next] | [standalone]

#1588579

Am 24.02.2017 um 20:49 schrieb Radim Krčmář:
> The leading underscores denote that the call is just a bitop wrapper.

Actually, the leading underscore is misleading

If we want to match the semantics of set/test/clear_bit, using a leading
underscore might feel like using the non-atomic variants like
__clear_bit and friends.

I'd prefer to simply drop the underscore.

-- 
Thanks,

David

[toc] | [prev] | [next] | [standalone]

#1588585

Am 27.02.2017 um 11:02 schrieb David Hildenbrand:
> Am 24.02.2017 um 20:49 schrieb Radim Krčmář:
>> The leading underscores denote that the call is just a bitop wrapper.
> 
> Actually, the leading underscore is misleading
> 
> If we want to match the semantics of set/test/clear_bit, using a leading
> underscore might feel like using the non-atomic variants like
> __clear_bit and friends.
> 
> I'd prefer to simply drop the underscore.
> 

Okay, this is not really possible for __kvm_request_set(). Hm.....

-- 
Thanks,

David

[toc] | [prev] | [next] | [standalone]

#1589248

On Fri, Feb 24, 2017 at 08:49:59PM +0100, Radim Krčmář wrote:
> The leading underscores denote that the call is just a bitop wrapper.
> 
> Switch all users of open-coded set/check/test to kvm_request ones.
> 
> Automated by coccinelle script:
>   @@
>   expression VCPU, REQ;
>   @@
>   -set_bit(REQ, &VCPU->requests)
>   +__kvm_request_set(REQ, VCPU)
> 
>   @@
>   expression VCPU, REQ;
>   @@
>   -clear_bit(REQ, &VCPU->requests)
>   +__kvm_request_clear(REQ, VCPU)
> 
>   @@
>   expression VCPU, REQ;
>   @@
>   -test_bit(REQ, &VCPU->requests)
>   +__kvm_request_test(REQ, VCPU)
> 
> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
> ---
>  v2: clear_bit in __kvm_request_clear [Paolo]
> ---
>  arch/mips/kvm/emulate.c           |  2 +-
>  arch/powerpc/kvm/book3s_pr.c      |  2 +-
>  arch/powerpc/kvm/book3s_pr_papr.c |  2 +-
>  arch/powerpc/kvm/booke.c          |  4 ++--
>  arch/powerpc/kvm/powerpc.c        |  2 +-
>  arch/s390/kvm/kvm-s390.c          |  2 +-
>  arch/x86/kvm/vmx.c                |  2 +-
>  arch/x86/kvm/x86.c                | 14 +++++++-------
>  include/linux/kvm_host.h          | 23 ++++++++++++++++++++---
>  9 files changed, 35 insertions(+), 18 deletions(-)
> 
> diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
> index ee4af898bcf6..552ae2b5e911 100644
> --- a/arch/mips/kvm/emulate.c
> +++ b/arch/mips/kvm/emulate.c
> @@ -865,7 +865,7 @@ enum emulation_result kvm_mips_emul_wait(struct kvm_vcpu *vcpu)
>  		 * check if any I/O interrupts are pending.
>  		 */
>  		if (kvm_request_test_and_clear(KVM_REQ_UNHALT, vcpu)) {
> -			clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
> +			__kvm_request_clear(KVM_REQ_UNHALT, vcpu);

Shall we just remove above line since we cleared it already?

-- peterx

[toc] | [prev] | [next] | [standalone]

#1589251

On Tue, Feb 28, 2017 at 03:34:24PM +0800, Peter Xu wrote:

[...]

> > diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
> > index ee4af898bcf6..552ae2b5e911 100644
> > --- a/arch/mips/kvm/emulate.c
> > +++ b/arch/mips/kvm/emulate.c
> > @@ -865,7 +865,7 @@ enum emulation_result kvm_mips_emul_wait(struct kvm_vcpu *vcpu)
> >  		 * check if any I/O interrupts are pending.
> >  		 */
> >  		if (kvm_request_test_and_clear(KVM_REQ_UNHALT, vcpu)) {
> > -			clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
> > +			__kvm_request_clear(KVM_REQ_UNHALT, vcpu);
> 
> Shall we just remove above line since we cleared it already?

Please ignore this since I see patch 4. :-)

It'll be nice if patch 4 will be before this one, but it's trivial.

Thanks,

-- peterx

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web