diff mbox series

KVM: X86: Use IPI shorthands in kvm guest when support

Message ID 1564121417-29375-1-git-send-email-wanpengli@tencent.com (mailing list archive)
State New, archived
Headers show
Series KVM: X86: Use IPI shorthands in kvm guest when support | expand

Commit Message

Wanpeng Li July 26, 2019, 6:10 a.m. UTC
From: Wanpeng Li <wanpengli@tencent.com>

IPI shorthand is supported now by linux apic/x2apic driver, switch to 
IPI shorthand for all excluding self and all including self destination 
shorthand in kvm guest, to avoid splitting the target mask into serveral 
PV IPI hypercalls.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Nadav Amit <namit@vmware.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
Note: rebase against tip tree's x86/apic branch

 arch/x86/kernel/kvm.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

Comments

Wanpeng Li July 26, 2019, 6:16 a.m. UTC | #1
On Fri, 26 Jul 2019 at 14:10, Wanpeng Li <kernellwp@gmail.com> wrote:
>
> From: Wanpeng Li <wanpengli@tencent.com>
>
> IPI shorthand is supported now by linux apic/x2apic driver, switch to
> IPI shorthand for all excluding self and all including self destination
> shorthand in kvm guest, to avoid splitting the target mask into serveral
> PV IPI hypercalls.
>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Cc: Sean Christopherson <sean.j.christopherson@intel.com>
> Cc: Nadav Amit <namit@vmware.com>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> ---
> Note: rebase against tip tree's x86/apic branch
>
>  arch/x86/kernel/kvm.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index b7f34fe..87b73b8 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -34,7 +34,9 @@
>  #include <asm/hypervisor.h>
>  #include <asm/tlb.h>
>
> +static struct apic orig_apic;
>  static int kvmapf = 1;
> +DECLARE_STATIC_KEY_FALSE(apic_use_ipi_shorthand);
>
>  static int __init parse_no_kvmapf(char *arg)
>  {
> @@ -507,12 +509,18 @@ static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
>
>  static void kvm_send_ipi_allbutself(int vector)
>  {
> -       kvm_send_ipi_mask_allbutself(cpu_online_mask, vector);
> +       if (static_branch_likely(&apic_use_ipi_shorthand))
> +               orig_apic.send_IPI_allbutself(vector);
> +       else
> +               kvm_send_ipi_mask_allbutself(cpu_online_mask, vector);
>  }
>
>  static void kvm_send_ipi_all(int vector)
>  {
> -       __send_ipi_mask(cpu_online_mask, vector);
> +       if (static_branch_likely(&apic_use_ipi_shorthand))
> +               orig_apic.send_IPI_allbutself(vector);

Make a mistake here, just resend the patch.

> +       else
> +               __send_ipi_mask(cpu_online_mask, vector);
>  }
>
>  /*
> @@ -520,6 +528,8 @@ static void kvm_send_ipi_all(int vector)
>   */
>  static void kvm_setup_pv_ipi(void)
>  {
> +       orig_apic = *apic;
> +
>         apic->send_IPI_mask = kvm_send_ipi_mask;
>         apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
>         apic->send_IPI_allbutself = kvm_send_ipi_allbutself;
> --
> 2.7.4
>
Thomas Gleixner July 26, 2019, 7:20 a.m. UTC | #2
On Fri, 26 Jul 2019, Wanpeng Li wrote:
> On Fri, 26 Jul 2019 at 14:10, Wanpeng Li <kernellwp@gmail.com> wrote:
> >  static void kvm_send_ipi_all(int vector)
> >  {
> > -       __send_ipi_mask(cpu_online_mask, vector);
> > +       if (static_branch_likely(&apic_use_ipi_shorthand))
> > +               orig_apic.send_IPI_allbutself(vector);
> 
> Make a mistake here, just resend the patch.

Please don't use [RESEND] if the patch is different. Use [PATCH v2].

[RESEND] is used when you actually resend an unmodified patch, e.g. when
the first submission was ignored for a longer time.

Thanks,

	tglx
Wanpeng Li July 26, 2019, 7:46 a.m. UTC | #3
On Fri, 26 Jul 2019 at 15:20, Thomas Gleixner <tglx@linutronix.de> wrote:
>
> On Fri, 26 Jul 2019, Wanpeng Li wrote:
> > On Fri, 26 Jul 2019 at 14:10, Wanpeng Li <kernellwp@gmail.com> wrote:
> > >  static void kvm_send_ipi_all(int vector)
> > >  {
> > > -       __send_ipi_mask(cpu_online_mask, vector);
> > > +       if (static_branch_likely(&apic_use_ipi_shorthand))
> > > +               orig_apic.send_IPI_allbutself(vector);
> >
> > Make a mistake here, just resend the patch.
>
> Please don't use [RESEND] if the patch is different. Use [PATCH v2].
>
> [RESEND] is used when you actually resend an unmodified patch, e.g. when
> the first submission was ignored for a longer time.

Will do for next time, I guess Paolo can still review the [RESEND] one
for this time to avoid my patch flush the mailing list. :)

Regards,
Wanpeng Li
diff mbox series

Patch

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index b7f34fe..87b73b8 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -34,7 +34,9 @@ 
 #include <asm/hypervisor.h>
 #include <asm/tlb.h>
 
+static struct apic orig_apic;
 static int kvmapf = 1;
+DECLARE_STATIC_KEY_FALSE(apic_use_ipi_shorthand);
 
 static int __init parse_no_kvmapf(char *arg)
 {
@@ -507,12 +509,18 @@  static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
 
 static void kvm_send_ipi_allbutself(int vector)
 {
-	kvm_send_ipi_mask_allbutself(cpu_online_mask, vector);
+	if (static_branch_likely(&apic_use_ipi_shorthand))
+		orig_apic.send_IPI_allbutself(vector);
+	else
+		kvm_send_ipi_mask_allbutself(cpu_online_mask, vector);
 }
 
 static void kvm_send_ipi_all(int vector)
 {
-	__send_ipi_mask(cpu_online_mask, vector);
+	if (static_branch_likely(&apic_use_ipi_shorthand))
+		orig_apic.send_IPI_allbutself(vector);
+	else
+		__send_ipi_mask(cpu_online_mask, vector);
 }
 
 /*
@@ -520,6 +528,8 @@  static void kvm_send_ipi_all(int vector)
  */
 static void kvm_setup_pv_ipi(void)
 {
+	orig_apic = *apic;
+
 	apic->send_IPI_mask = kvm_send_ipi_mask;
 	apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
 	apic->send_IPI_allbutself = kvm_send_ipi_allbutself;