| Message ID | 20170426203227.12321-5-rkrcmar@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Apr 26, 2017 at 10:32:22PM +0200, Radim Krčmář wrote: > 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> > --- > v2: use GENMASK [Marc] > --- > arch/arm/include/asm/kvm_host.h | 2 +- > arch/arm64/include/asm/kvm_host.h | 2 +- > arch/x86/include/asm/kvm_host.h | 6 +++--- > include/linux/kvm_host.h | 12 +++++++----- > 4 files changed, 12 insertions(+), 10 deletions(-) Reviewed-by: Andrew Jones <drjones@redhat.com>
On Wed, 26 Apr 2017 22:32:22 +0200 Radim Krčmář <rkrcmar@redhat.com> wrote: > 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> > --- > v2: use GENMASK [Marc] > --- > arch/arm/include/asm/kvm_host.h | 2 +- > arch/arm64/include/asm/kvm_host.h | 2 +- > arch/x86/include/asm/kvm_host.h | 6 +++--- > include/linux/kvm_host.h | 12 +++++++----- > 4 files changed, 12 insertions(+), 10 deletions(-) Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index de67ce647501..49358f20d36f 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -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); diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 522e4f60976e..1c9458a7ec92 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -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); diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f5c942edbc86..19219826bed6 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -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 diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 374fa92c7657..a805ddcb7eb0 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -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)
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> --- v2: use GENMASK [Marc] --- arch/arm/include/asm/kvm_host.h | 2 +- arch/arm64/include/asm/kvm_host.h | 2 +- arch/x86/include/asm/kvm_host.h | 6 +++--- include/linux/kvm_host.h | 12 +++++++----- 4 files changed, 12 insertions(+), 10 deletions(-)