KVM: x86: Switch KVM guest to using interrupts for page ready APF delivery (b1d40575) · Commits · 戴 / test

arch/x86/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -801,6 +801,7 @@ config KVM_GUEST
		depends on PARAVIRT
		select PARAVIRT_CLOCK
		select ARCH_CPUIDLE_HALTPOLL
		select X86_HV_CALLBACK_VECTOR
		default y
		---help---
		This option enables various optimizations for running under the KVM

arch/x86/entry/entry_32.S

+5 −0

Original line number	Diff line number	Diff line
		@@ -1475,6 +1475,11 @@ BUILD_INTERRUPT3(hv_stimer0_callback_vector, HYPERV_STIMER0_VECTOR,

		#endif /* CONFIG_HYPERV */

		#ifdef CONFIG_KVM_GUEST
		BUILD_INTERRUPT3(kvm_async_pf_vector, HYPERVISOR_CALLBACK_VECTOR,
		kvm_async_pf_intr)
		#endif

		SYM_CODE_START(page_fault)
		ASM_CLAC
		pushl $do_page_fault

arch/x86/entry/entry_64.S

+5 −0

Original line number	Diff line number	Diff line
		@@ -1190,6 +1190,11 @@ apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \
		acrn_hv_callback_vector acrn_hv_vector_handler
		#endif

		#ifdef CONFIG_KVM_GUEST
		apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \
		kvm_async_pf_vector kvm_async_pf_intr
		#endif

		idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=IST_INDEX_DB ist_offset=DB_STACK_OFFSET
		idtentry int3 do_int3 has_error_code=0 create_gap=1
		idtentry stack_segment do_stack_segment has_error_code=1

arch/x86/include/asm/kvm_para.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -4,6 +4,7 @@

		#include <asm/processor.h>
		#include <asm/alternative.h>
		#include <linux/interrupt.h>
		#include <uapi/asm/kvm_para.h>

		extern void kvmclock_init(void);
		@@ -104,6 +105,12 @@ static __always_inline bool kvm_handle_async_pf(struct pt_regs *regs, u32 token)
		return false;
		}

		extern __visible void kvm_async_pf_vector(void);
		#ifdef CONFIG_TRACING
		#define trace_kvm_async_pf_vector kvm_async_pf_vector
		#endif
		__visible void __irq_entry kvm_async_pf_intr(struct pt_regs *regs);

		#ifdef CONFIG_PARAVIRT_SPINLOCKS
		void __init kvm_spinlock_init(void);
		#else /* !CONFIG_PARAVIRT_SPINLOCKS */

arch/x86/kernel/kvm.c

+33 −15

Original line number	Diff line number	Diff line
		@@ -233,15 +233,10 @@ NOKPROBE_SYMBOL(kvm_read_and_reset_apf_flags);

		bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
		{
		u32 reason = kvm_read_and_reset_apf_flags();
		u32 flags = kvm_read_and_reset_apf_flags();

		switch (reason) {
		case KVM_PV_REASON_PAGE_NOT_PRESENT:
		case KVM_PV_REASON_PAGE_READY:
		break;
		default:
		if (!flags)
		return false;
		}

		/*
		* If the host managed to inject an async #PF into an interrupt
		@@ -251,19 +246,38 @@ bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
		if (unlikely(!(regs->flags & X86_EFLAGS_IF)))
		panic("Host injected async #PF in interrupt disabled region\n");

		if (reason == KVM_PV_REASON_PAGE_NOT_PRESENT) {
		if (flags & KVM_PV_REASON_PAGE_NOT_PRESENT) {
		if (unlikely(!(user_mode(regs))))
		panic("Host injected async #PF in kernel mode\n");
		/* Page is swapped out by the host. */
		kvm_async_pf_task_wait_schedule(token);
		} else {
		return true;
		}

		WARN_ONCE(1, "Unexpected async PF flags: %x\n", flags);
		return true;
		}
		NOKPROBE_SYMBOL(__kvm_handle_async_pf);

		__visible void __irq_entry kvm_async_pf_intr(struct pt_regs *regs)
		{
		u32 token;

		entering_ack_irq();

		inc_irq_stat(irq_hv_callback_count);

		if (__this_cpu_read(apf_reason.enabled)) {
		token = __this_cpu_read(apf_reason.token);
		rcu_irq_enter();
		kvm_async_pf_task_wake(token);
		rcu_irq_exit();
		__this_cpu_write(apf_reason.token, 0);
		wrmsrl(MSR_KVM_ASYNC_PF_ACK, 1);
		}
		return true;

		exiting_irq();
		}
		NOKPROBE_SYMBOL(__kvm_handle_async_pf);

		static void __init paravirt_ops_setup(void)
		{
		@@ -308,17 +322,19 @@ static notrace void kvm_guest_apic_eoi_write(u32 reg, u32 val)

		static void kvm_guest_cpu_init(void)
		{
		if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {
		u64 pa;
		if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) {
		u64 pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));

		WARN_ON_ONCE(!static_branch_likely(&kvm_async_pf_enabled));

		pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
		pa \|= KVM_ASYNC_PF_ENABLED;
		pa \|= KVM_ASYNC_PF_ENABLED \| KVM_ASYNC_PF_DELIVERY_AS_INT;

		if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_VMEXIT))
		pa \|= KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT;

		wrmsrl(MSR_KVM_ASYNC_PF_INT, HYPERVISOR_CALLBACK_VECTOR);

		wrmsrl(MSR_KVM_ASYNC_PF_EN, pa);
		__this_cpu_write(apf_reason.enabled, 1);
		pr_info("KVM setup async PF for cpu %d\n", smp_processor_id());
		@@ -643,8 +659,10 @@ static void __init kvm_guest_init(void)
		if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
		apic_set_eoi_write(kvm_guest_apic_eoi_write);

		if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf)
		if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) {
		static_branch_enable(&kvm_async_pf_enabled);
		alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, kvm_async_pf_vector);
		}

		#ifdef CONFIG_SMP
		smp_ops.smp_prepare_cpus = kvm_smp_prepare_cpus;

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