KVM: mark requests that do not need a wakeup

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>

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index de67ce64750173c019703bef1d38ee622bd1a91d..49358f20d36f4493ae1551f183d6af4f695a095f 100644 (file)
--- 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 522e4f60976ee1e6939cbb48c302552708c863e1..1c9458a7ec92eae20d42f8285a9352c6fcced0b3 100644 (file)
--- 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 f5c942edbc86c050ca595aa450b3a254c15f2233..19219826bed6bb7aa150c202ff7d8b8f8107ca11 100644 (file)
--- 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 374fa92c7657784b0c3c05472b64e9bbd7db0a04..a805ddcb7eb050a124f2143cd0c995acf58883e4 100644 (file)
--- 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)