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- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
- "Suthikulpanit, Suravee"
| | | Subject | Re: [PATCH v2 12/15] kvm: i8254: Check LAPIC EOI pending when injecting irq on SVM AVIC | From | Alexander Graf <> | Date | Mon, 19 Aug 2019 12:42:31 +0200 |
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On 15.08.19 18:25, Suthikulpanit, Suravee wrote: > ACK notifiers don't work with AMD SVM w/ AVIC when the PIT interrupt > is delivered as edge-triggered fixed interrupt since AMD processors > cannot exit on EOI for these interrupts. > > Add code to check LAPIC pending EOI before injecting any pending PIT > interrupt on AMD SVM when AVIC is activated. > > Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> > --- > arch/x86/kvm/i8254.c | 31 +++++++++++++++++++++++++------ > 1 file changed, 25 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c > index 4a6dc54..31c4a9b 100644 > --- a/arch/x86/kvm/i8254.c > +++ b/arch/x86/kvm/i8254.c > @@ -34,10 +34,12 @@ > > #include <linux/kvm_host.h> > #include <linux/slab.h> > +#include <asm/virtext.h> > > #include "ioapic.h" > #include "irq.h" > #include "i8254.h" > +#include "lapic.h" > #include "x86.h" > > #ifndef CONFIG_X86_64 > @@ -236,6 +238,12 @@ static void destroy_pit_timer(struct kvm_pit *pit) > kthread_flush_work(&pit->expired); > } > > +static inline void kvm_pit_reset_reinject(struct kvm_pit *pit) > +{ > + atomic_set(&pit->pit_state.pending, 0); > + atomic_set(&pit->pit_state.irq_ack, 1); > +} > + > static void pit_do_work(struct kthread_work *work) > { > struct kvm_pit *pit = container_of(work, struct kvm_pit, expired); > @@ -244,6 +252,23 @@ static void pit_do_work(struct kthread_work *work) > int i; > struct kvm_kpit_state *ps = &pit->pit_state; > > + /* > + * Since, AMD SVM AVIC accelerates write access to APIC EOI > + * register for edge-trigger interrupts. PIT will not be able > + * to receive the IRQ ACK notifier and will always be zero. > + * Therefore, we check if any LAPIC EOI pending for vector 0 > + * and reset irq_ack if no pending. > + */ > + if (cpu_has_svm(NULL) && kvm->arch.apicv_state == APICV_ACTIVATED) { > + int eoi = 0; > + > + kvm_for_each_vcpu(i, vcpu, kvm) > + if (kvm_apic_pending_eoi(vcpu, 0)) > + eoi++; > + if (!eoi) > + kvm_pit_reset_reinject(pit);
In which case would eoi be != 0 when APIC-V is active?
Alex
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