KVM: Update Posted-Interrupts Descriptor when vCPU is preempted (28b835d6) · Commits · 戴 / test

arch/x86/kvm/vmx.c

+80 −0

Original line number	Diff line number	Diff line
		@@ -35,6 +35,7 @@
		#include "kvm_cache_regs.h"
		#include "x86.h"

		#include <asm/cpu.h>
		#include <asm/io.h>
		#include <asm/desc.h>
		#include <asm/vmx.h>
		@@ -1942,6 +1943,52 @@ static void vmx_load_host_state(struct vcpu_vmx *vmx)
		preempt_enable();
		}

		static void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu)
		{
		struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu);
		struct pi_desc old, new;
		unsigned int dest;

		if (!kvm_arch_has_assigned_device(vcpu->kvm) \|\|
		!irq_remapping_cap(IRQ_POSTING_CAP))
		return;

		do {
		old.control = new.control = pi_desc->control;

		/*
		* If 'nv' field is POSTED_INTR_WAKEUP_VECTOR, there
		* are two possible cases:
		* 1. After running 'pre_block', context switch
		* happened. For this case, 'sn' was set in
		* vmx_vcpu_put(), so we need to clear it here.
		* 2. After running 'pre_block', we were blocked,
		* and woken up by some other guy. For this case,
		* we don't need to do anything, 'pi_post_block'
		* will do everything for us. However, we cannot
		* check whether it is case #1 or case #2 here
		* (maybe, not needed), so we also clear sn here,
		* I think it is not a big deal.
		*/
		if (pi_desc->nv != POSTED_INTR_WAKEUP_VECTOR) {
		if (vcpu->cpu != cpu) {
		dest = cpu_physical_id(cpu);

		if (x2apic_enabled())
		new.ndst = dest;
		else
		new.ndst = (dest << 8) & 0xFF00;
		}

		/* set 'NV' to 'notification vector' */
		new.nv = POSTED_INTR_VECTOR;
		}

		/* Allow posting non-urgent interrupts */
		new.sn = 0;
		} while (cmpxchg(&pi_desc->control, old.control,
		new.control) != old.control);
		}
		/*
		* Switches to specified vcpu, until a matching vcpu_put(), but assumes
		* vcpu mutex is already taken.
		@@ -1992,10 +2039,27 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
		vmcs_writel(HOST_IA32_SYSENTER_ESP, sysenter_esp); /* 22.2.3 */
		vmx->loaded_vmcs->cpu = cpu;
		}

		vmx_vcpu_pi_load(vcpu, cpu);
		}

		static void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu)
		{
		struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu);

		if (!kvm_arch_has_assigned_device(vcpu->kvm) \|\|
		!irq_remapping_cap(IRQ_POSTING_CAP))
		return;

		/* Set SN when the vCPU is preempted */
		if (vcpu->preempted)
		pi_set_sn(pi_desc);
		}

		static void vmx_vcpu_put(struct kvm_vcpu *vcpu)
		{
		vmx_vcpu_pi_put(vcpu);

		__vmx_load_host_state(to_vmx(vcpu));
		if (!vmm_exclusive) {
		__loaded_vmcs_clear(to_vmx(vcpu)->loaded_vmcs);
		@@ -4427,6 +4491,22 @@ static inline bool kvm_vcpu_trigger_posted_interrupt(struct kvm_vcpu *vcpu)
		{
		#ifdef CONFIG_SMP
		if (vcpu->mode == IN_GUEST_MODE) {
		struct vcpu_vmx *vmx = to_vmx(vcpu);

		/*
		* Currently, we don't support urgent interrupt,
		* all interrupts are recognized as non-urgent
		* interrupt, so we cannot post interrupts when
		* 'SN' is set.
		*
		* If the vcpu is in guest mode, it means it is
		* running instead of being scheduled out and
		* waiting in the run queue, and that's the only
		* case when 'SN' is set currently, warning if
		* 'SN' is set.
		*/
		WARN_ON_ONCE(pi_test_sn(&vmx->pi_desc));

		apic->send_IPI_mask(get_cpu_mask(vcpu->cpu),
		POSTED_INTR_VECTOR);
		return true;

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