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apic: Defer interrupt updates to VCPU thread

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KVM performs TPR raising asynchronously to QEMU, specifically outside
QEMU's global lock. When an interrupt is injected into the APIC and TPR
is checked to decide if this can be delivered, a stale TPR value may be
used, causing spurious interrupts in the end.

Fix this by deferring apic_update_irq to the context of the target VCPU.
We introduce a new interrupt flag for this, CPU_INTERRUPT_POLL. When it
is set, the VCPU calls apic_poll_irq before checking for further pending
interrupts. To avoid special-casing KVM, we also implement this logic
for TCG mode.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Jan Kiszka 2012-07-09 16:42:32 +02:00 • committed by Avi Kivity
parent a94820ddc3
commit 5d62c43a17
6 changed files with 18 additions and 3 deletions
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1
hw/apic_internal.h
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@ -141,7 +141,6 @@ void apic_report_irq_delivered(int delivered);
bool apic_next_timer(APICCommonState *s, int64_t current_time);
void apic_enable_tpr_access_reporting(DeviceState *d, bool enable);
void apic_enable_vapic(DeviceState *d, target_phys_addr_t paddr);
void apic_poll_irq(DeviceState *d);
void vapic_report_tpr_access(DeviceState *dev, void *cpu, target_ulong ip,
TPRAccess access);