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KVM: mark requests that do not need a wakeup

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Some operations must ensure that the guest is not running with stale
data, but if the guest is halted, then the update can wait until another
event happens.  kvm_make_all_requests() currently doesn't wake up, so we
can mark all requests used with it.

First 8 bits were arbitrarily reserved for request numbers.

Most uses of requests have the request type as a constant, so a compiler
will optimize the '&'.

An alternative would be to have an inline function that would return
whether the request needs a wake-up or not, but I like this one better
even though it might produce worse assembly.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Radim Krčmář 2017-04-26 22:32:22 +02:00 committed by Paolo Bonzini
parent 75aaafb79f
commit 930f7fd6da
4 changed files with 12 additions and 10 deletions
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2
arch/arm/include/asm/kvm_host.h
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@ -44,7 +44,7 @@
#define KVM_MAX_VCPUS VGIC_V2_MAX_CPUS
#endif
#define KVM_REQ_VCPU_EXIT 8
#define KVM_REQ_VCPU_EXIT (8 | KVM_REQUEST_NO_WAKEUP)
u32 *kvm_vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num, u32 mode);
int __attribute_const__ kvm_target_cpu(void);

2
arch/arm64/include/asm/kvm_host.h
View File

@ -41,7 +41,7 @@
#define KVM_VCPU_MAX_FEATURES 4
#define KVM_REQ_VCPU_EXIT 8
#define KVM_REQ_VCPU_EXIT (8 | KVM_REQUEST_NO_WAKEUP)
int __attribute_const__ kvm_target_cpu(void);
int kvm_reset_vcpu(struct kvm_vcpu *vcpu);

6
arch/x86/include/asm/kvm_host.h
View File

@ -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
#define KVM_REQ_SCAN_IOAPIC 23
#define KVM_REQ_MCLOCK_INPROGRESS (22 | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_SCAN_IOAPIC (23 | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_GLOBAL_CLOCK_UPDATE 24
#define KVM_REQ_APIC_PAGE_RELOAD 25
#define KVM_REQ_APIC_PAGE_RELOAD (25 | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_HV_CRASH 26
#define KVM_REQ_IOAPIC_EOI_EXIT 27
#define KVM_REQ_HV_RESET 28

12
include/linux/kvm_host.h
View File

@ -115,12 +115,14 @@ static inline bool is_error_page(struct page *page)
return IS_ERR(page);
}
#define KVM_REQUEST_MASK GENMASK(7,0)
#define KVM_REQUEST_NO_WAKEUP BIT(8)
/*
* Architecture-independent vcpu->requests bit members
* Bits 4-7 are reserved for more arch-independent bits.
*/
#define KVM_REQ_TLB_FLUSH 0
#define KVM_REQ_MMU_RELOAD 1
#define KVM_REQ_TLB_FLUSH (0 | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_MMU_RELOAD (1 | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_PENDING_TIMER 2
#define KVM_REQ_UNHALT 3
@ -1076,17 +1078,17 @@ static inline void kvm_make_request(int req, struct kvm_vcpu *vcpu)
* caller. Paired with the smp_mb__after_atomic in kvm_check_request.
*/
smp_wmb();
set_bit(req, &vcpu->requests);
set_bit(req & KVM_REQUEST_MASK, &vcpu->requests);
}
static inline bool kvm_test_request(int req, struct kvm_vcpu *vcpu)
{
return test_bit(req, &vcpu->requests);
return test_bit(req & KVM_REQUEST_MASK, &vcpu->requests);
}
static inline void kvm_clear_request(int req, struct kvm_vcpu *vcpu)
{
clear_bit(req, &vcpu->requests);
clear_bit(req & KVM_REQUEST_MASK, &vcpu->requests);
}
static inline bool kvm_check_request(int req, struct kvm_vcpu *vcpu)