Commit 7495e22b authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: Move running VCPU from ARM to common code 



For ring-based dirty log tracking, it will be more efficient to account
writes during schedule-out or schedule-in to the currently running VCPU.
We would like to do it even if the write doesn't use the current VCPU's
address space, as is the case for cached writes (see commit 4e335d9e,
"Revert "KVM: Support vCPU-based gfn->hva cache"", 2017-05-02).

Therefore, add a mechanism to track the currently-loaded kvm_vcpu struct.
There is already something similar in KVM/ARM; one important difference
is that kvm_arch_vcpu_{load,put} have two callers in virt/kvm/kvm_main.c:
we have to update both the architecture-independent vcpu_{load,put} and
the preempt notifiers.

Another change made in the process is to allow using kvm_get_running_vcpu()
in preemptible code.  This is allowed because preempt notifiers ensure
that the value does not change even after the VCPU thread is migrated.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 6a3c623b

arch/arm/include/asm/kvm_host.h

+0 −2
Original line number Diff line number Diff line
@@ -284,8 +284,6 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices); 
int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end);

int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);



struct kvm_vcpu *kvm_arm_get_running_vcpu(void);

struct kvm_vcpu __percpu **kvm_get_running_vcpus(void);

void kvm_arm_halt_guest(struct kvm *kvm);

void kvm_arm_resume_guest(struct kvm *kvm);

arch/arm64/include/asm/kvm_host.h

+0 −2
Original line number Diff line number Diff line
@@ -446,8 +446,6 @@ int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte); 
int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end);

int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);



struct kvm_vcpu *kvm_arm_get_running_vcpu(void);

struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void);

void kvm_arm_halt_guest(struct kvm *kvm);

void kvm_arm_resume_guest(struct kvm *kvm);

include/linux/kvm_host.h

+3 −0
Original line number Diff line number Diff line
@@ -1335,6 +1335,9 @@ static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val) 
}

#endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */



struct kvm_vcpu *kvm_get_running_vcpu(void);

struct kvm_vcpu __percpu **kvm_get_running_vcpus(void);



#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS

bool kvm_arch_has_irq_bypass(void);

int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *,

virt/kvm/arm/arch_timer.c

+1 −1
Original line number Diff line number Diff line
@@ -1022,7 +1022,7 @@ static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu) 


bool kvm_arch_timer_get_input_level(int vintid)

{

	struct kvm_vcpu *vcpu = kvm_arm_get_running_vcpu();

	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();

	struct arch_timer_context *timer;



	if (vintid == vcpu_vtimer(vcpu)->irq.irq)

virt/kvm/arm/arm.c

+0 −29
Original line number Diff line number Diff line
@@ -51,9 +51,6 @@ __asm__(".arch_extension virt"); 
DEFINE_PER_CPU(kvm_host_data_t, kvm_host_data);

static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);



/* Per-CPU variable containing the currently running vcpu. */

static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_arm_running_vcpu);



/* The VMID used in the VTTBR */

static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1);

static u32 kvm_next_vmid;
@@ -62,31 +59,8 @@ static DEFINE_SPINLOCK(kvm_vmid_lock); 
static bool vgic_present;



static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled);



static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)

{

	__this_cpu_write(kvm_arm_running_vcpu, vcpu);

}



DEFINE_STATIC_KEY_FALSE(userspace_irqchip_in_use);



/**

 * kvm_arm_get_running_vcpu - get the vcpu running on the current CPU.

 * Must be called from non-preemptible context

 */

struct kvm_vcpu *kvm_arm_get_running_vcpu(void)

{

	return __this_cpu_read(kvm_arm_running_vcpu);

}



/**

 * kvm_arm_get_running_vcpus - get the per-CPU array of currently running vcpus.

 */

struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void)

{

	return &kvm_arm_running_vcpu;

}



int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)

{

	return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
@@ -380,7 +354,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) 
	vcpu->cpu = cpu;

	vcpu->arch.host_cpu_context = &cpu_data->host_ctxt;



	kvm_arm_set_running_vcpu(vcpu);

	kvm_vgic_load(vcpu);

	kvm_timer_vcpu_load(vcpu);

	kvm_vcpu_load_sysregs(vcpu);
@@ -406,8 +379,6 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) 
	kvm_vcpu_pmu_restore_host(vcpu);



	vcpu->cpu = -1;



	kvm_arm_set_running_vcpu(NULL);

}



static void vcpu_power_off(struct kvm_vcpu *vcpu)