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Commit 7a97cec2 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: mark requests that need synchronization 



kvm_make_all_requests() provides a synchronization that waits until all
kicked VCPUs have acknowledged the kick.  This is important for
KVM_REQ_MMU_RELOAD as it prevents freeing while lockless paging is
underway.

This patch adds the synchronization property into all requests that are
currently being used with kvm_make_all_requests() in order to preserve
the current behavior and only introduce a new framework.  Removing it
from requests where it is not necessary is left for future patches.

Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 178f02ff

arch/arm/include/asm/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -44,7 +44,7 @@ 
#define KVM_MAX_VCPUS VGIC_V2_MAX_CPUS

#endif



#define KVM_REQ_VCPU_EXIT	(8 | KVM_REQUEST_NO_WAKEUP)

#define KVM_REQ_VCPU_EXIT	(8 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)



u32 *kvm_vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num, u32 mode);

int __attribute_const__ kvm_target_cpu(void);

arch/arm64/include/asm/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -41,7 +41,7 @@ 


#define KVM_VCPU_MAX_FEATURES 4



#define KVM_REQ_VCPU_EXIT	(8 | KVM_REQUEST_NO_WAKEUP)

#define KVM_REQ_VCPU_EXIT	(8 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)



int __attribute_const__ kvm_target_cpu(void);

int kvm_reset_vcpu(struct kvm_vcpu *vcpu);

arch/x86/include/asm/kvm_host.h

+3 −3
Original line number Diff line number Diff line
@@ -61,10 +61,10 @@ 
#define KVM_REQ_PMI               19

#define KVM_REQ_SMI               20

#define KVM_REQ_MASTERCLOCK_UPDATE 21

#define KVM_REQ_MCLOCK_INPROGRESS (22 | KVM_REQUEST_NO_WAKEUP)

#define KVM_REQ_SCAN_IOAPIC       (23 | KVM_REQUEST_NO_WAKEUP)

#define KVM_REQ_MCLOCK_INPROGRESS (22 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)

#define KVM_REQ_SCAN_IOAPIC       (23 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)

#define KVM_REQ_GLOBAL_CLOCK_UPDATE 24

#define KVM_REQ_APIC_PAGE_RELOAD  (25 | KVM_REQUEST_NO_WAKEUP)

#define KVM_REQ_APIC_PAGE_RELOAD  (25 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)

#define KVM_REQ_HV_CRASH          26

#define KVM_REQ_IOAPIC_EOI_EXIT   27

#define KVM_REQ_HV_RESET          28

include/linux/kvm_host.h

+5 −4
Original line number Diff line number Diff line
@@ -117,12 +117,13 @@ static inline bool is_error_page(struct page *page) 


#define KVM_REQUEST_MASK           GENMASK(7,0)

#define KVM_REQUEST_NO_WAKEUP      BIT(8)

#define KVM_REQUEST_WAIT           BIT(9)

/*

 * Architecture-independent vcpu->requests bit members

 * Bits 4-7 are reserved for more arch-independent bits.

 */

#define KVM_REQ_TLB_FLUSH          (0 | KVM_REQUEST_NO_WAKEUP)

#define KVM_REQ_MMU_RELOAD         (1 | KVM_REQUEST_NO_WAKEUP)

#define KVM_REQ_TLB_FLUSH         (0 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)

#define KVM_REQ_MMU_RELOAD        (1 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)

#define KVM_REQ_PENDING_TIMER     2

#define KVM_REQ_UNHALT            3

virt/kvm/kvm_main.c

+22 −3
Original line number Diff line number Diff line
@@ -165,6 +165,24 @@ void vcpu_put(struct kvm_vcpu *vcpu) 
}

EXPORT_SYMBOL_GPL(vcpu_put);



/* TODO: merge with kvm_arch_vcpu_should_kick */

static bool kvm_request_needs_ipi(struct kvm_vcpu *vcpu, unsigned req)

{

	int mode = kvm_vcpu_exiting_guest_mode(vcpu);



	/*

	 * We need to wait for the VCPU to reenable interrupts and get out of

	 * READING_SHADOW_PAGE_TABLES mode.

	 */

	if (req & KVM_REQUEST_WAIT)

		return mode != OUTSIDE_GUEST_MODE;



	/*

	 * Need to kick a running VCPU, but otherwise there is nothing to do.

	 */

	return mode == IN_GUEST_MODE;

}



static void ack_flush(void *_completed)

{

}
@@ -174,6 +192,7 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req) 
	int i, cpu, me;

	cpumask_var_t cpus;

	bool called = true;

	bool wait = req & KVM_REQUEST_WAIT;

	struct kvm_vcpu *vcpu;



	zalloc_cpumask_var(&cpus, GFP_ATOMIC);
@@ -187,13 +206,13 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req) 
			continue;



		if (cpus != NULL && cpu != -1 && cpu != me &&

		      kvm_vcpu_exiting_guest_mode(vcpu) != OUTSIDE_GUEST_MODE)

		    kvm_request_needs_ipi(vcpu, req))

			cpumask_set_cpu(cpu, cpus);

	}

	if (unlikely(cpus == NULL))

		smp_call_function_many(cpu_online_mask, ack_flush, NULL, 1);

		smp_call_function_many(cpu_online_mask, ack_flush, NULL, wait);

	else if (!cpumask_empty(cpus))

		smp_call_function_many(cpus, ack_flush, NULL, 1);

		smp_call_function_many(cpus, ack_flush, NULL, wait);

	else

		called = false;

	put_cpu();