On Thu, 22 Sep 2022 01:32:11 +0100, Gavin Shan <[email protected]> wrote: > > This enables the ring-based dirty memory tracking on ARM64. The > feature is configured by CONFIG_HAVE_KVM_DIRTY_RING, detected and > enabled by KVM_CAP_DIRTY_LOG_RING. A ring buffer is created on every > VCPU when the feature is enabled. Each entry in the ring buffer is > described by 'struct kvm_dirty_gfn'. > > A ring buffer entry is pushed when a page becomes dirty on host, > and pulled by userspace after the ring buffer is mapped at physical > page offset KVM_DIRTY_LOG_PAGE_OFFSET. The specific VCPU is enforced > to exit if its ring buffer becomes softly full. Besides, the ring > buffer can be reset by ioctl command KVM_RESET_DIRTY_RINGS to release > those pulled ring buffer entries.
I think you can cut this message short. This description was useful when the feature was initially merged, but this is only a "plumb the damn thing" patch. > > Signed-off-by: Gavin Shan <[email protected]> > --- > Documentation/virt/kvm/api.rst | 2 +- > arch/arm64/include/uapi/asm/kvm.h | 1 + > arch/arm64/kvm/Kconfig | 1 + > arch/arm64/kvm/arm.c | 8 ++++++++ > 4 files changed, 11 insertions(+), 1 deletion(-) > > diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst > index abd7c32126ce..19fa1ac017ed 100644 > --- a/Documentation/virt/kvm/api.rst > +++ b/Documentation/virt/kvm/api.rst > @@ -8022,7 +8022,7 @@ regardless of what has actually been exposed through > the CPUID leaf. > 8.29 KVM_CAP_DIRTY_LOG_RING > --------------------------- > > -:Architectures: x86 > +:Architectures: x86, arm64 > :Parameters: args[0] - size of the dirty log ring > > KVM is capable of tracking dirty memory using ring buffers that are > diff --git a/arch/arm64/include/uapi/asm/kvm.h > b/arch/arm64/include/uapi/asm/kvm.h > index 316917b98707..a7a857f1784d 100644 > --- a/arch/arm64/include/uapi/asm/kvm.h > +++ b/arch/arm64/include/uapi/asm/kvm.h > @@ -43,6 +43,7 @@ > #define __KVM_HAVE_VCPU_EVENTS > > #define KVM_COALESCED_MMIO_PAGE_OFFSET 1 > +#define KVM_DIRTY_LOG_PAGE_OFFSET 64 > > #define KVM_REG_SIZE(id) \ > (1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT)) > diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig > index 815cc118c675..0309b2d0f2da 100644 > --- a/arch/arm64/kvm/Kconfig > +++ b/arch/arm64/kvm/Kconfig > @@ -32,6 +32,7 @@ menuconfig KVM > select KVM_VFIO > select HAVE_KVM_EVENTFD > select HAVE_KVM_IRQFD > + select HAVE_KVM_DIRTY_RING > select HAVE_KVM_MSI > select HAVE_KVM_IRQCHIP > select HAVE_KVM_IRQ_ROUTING > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index 2ff0ef62abad..76816f8e082b 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -747,6 +747,14 @@ static int check_vcpu_requests(struct kvm_vcpu *vcpu) > > if (kvm_check_request(KVM_REQ_SUSPEND, vcpu)) > return kvm_vcpu_suspend(vcpu); > + > + if (kvm_check_request(KVM_REQ_RING_SOFT_FULL, vcpu) && > + kvm_dirty_ring_soft_full(&vcpu->dirty_ring)) { > + kvm_make_request(KVM_REQ_RING_SOFT_FULL, vcpu); > + vcpu->run->exit_reason = KVM_EXIT_DIRTY_RING_FULL; > + trace_kvm_dirty_ring_exit(vcpu); > + return 0; > + } This is *very* similar to the x86 code. Could we move it to common code? Something like the diff below, to be for most of it squashed into patch #1. Thanks, M. diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 76816f8e082b..93a16cdbe163 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -748,13 +748,8 @@ static int check_vcpu_requests(struct kvm_vcpu *vcpu) if (kvm_check_request(KVM_REQ_SUSPEND, vcpu)) return kvm_vcpu_suspend(vcpu); - if (kvm_check_request(KVM_REQ_RING_SOFT_FULL, vcpu) && - kvm_dirty_ring_soft_full(&vcpu->dirty_ring)) { - kvm_make_request(KVM_REQ_RING_SOFT_FULL, vcpu); - vcpu->run->exit_reason = KVM_EXIT_DIRTY_RING_FULL; - trace_kvm_dirty_ring_exit(vcpu); + if (kvm_dirty_ring_check_request(vcpu)) return 0; - } } return 1; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index eb7d0d7654bb..48f2519b1db7 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10249,11 +10249,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) if (kvm_request_pending(vcpu)) { /* Forbid vmenter if vcpu dirty ring is soft-full */ - if (kvm_check_request(KVM_REQ_RING_SOFT_FULL, vcpu) && - kvm_dirty_ring_soft_full(&vcpu->dirty_ring)) { - kvm_make_request(KVM_REQ_RING_SOFT_FULL, vcpu); - vcpu->run->exit_reason = KVM_EXIT_DIRTY_RING_FULL; - trace_kvm_dirty_ring_exit(vcpu); + if (kvm_dirty_ring_check_request(vcpu)) { r = 0; goto out; } diff --git a/include/linux/kvm_dirty_ring.h b/include/linux/kvm_dirty_ring.h index 8c6755981c9b..6e484220adc0 100644 --- a/include/linux/kvm_dirty_ring.h +++ b/include/linux/kvm_dirty_ring.h @@ -64,11 +64,6 @@ static inline void kvm_dirty_ring_free(struct kvm_dirty_ring *ring) { } -static inline bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring) -{ - return true; -} - #else /* CONFIG_HAVE_KVM_DIRTY_RING */ int kvm_cpu_dirty_log_size(void); @@ -91,7 +86,7 @@ void kvm_dirty_ring_push(struct kvm_dirty_ring *ring, u32 slot, u64 offset); struct page *kvm_dirty_ring_get_page(struct kvm_dirty_ring *ring, u32 offset); void kvm_dirty_ring_free(struct kvm_dirty_ring *ring); -bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring); +bool kvm_dirty_ring_check_request(struct kvm_vcpu *vcpu); #endif /* CONFIG_HAVE_KVM_DIRTY_RING */ diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c index 69c8c90d489d..436d7cded5bf 100644 --- a/virt/kvm/dirty_ring.c +++ b/virt/kvm/dirty_ring.c @@ -26,7 +26,7 @@ static u32 kvm_dirty_ring_used(struct kvm_dirty_ring *ring) return READ_ONCE(ring->dirty_index) - READ_ONCE(ring->reset_index); } -bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring) +static bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring) { return kvm_dirty_ring_used(ring) >= ring->soft_limit; } @@ -182,3 +182,16 @@ void kvm_dirty_ring_free(struct kvm_dirty_ring *ring) vfree(ring->dirty_gfns); ring->dirty_gfns = NULL; } + +bool kvm_dirty_ring_check_request(struct kvm_vcpu *vcpu) +{ + if (kvm_check_request(KVM_REQ_RING_SOFT_FULL, vcpu) && + kvm_dirty_ring_soft_full(&vcpu->dirty_ring)) { + kvm_make_request(KVM_REQ_RING_SOFT_FULL, vcpu); + vcpu->run->exit_reason = KVM_EXIT_DIRTY_RING_FULL; + trace_kvm_dirty_ring_exit(vcpu); + return true; + } + + return false; +} -- Without deviation from the norm, progress is not possible. _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
