From: Gavin Shan <gshan@redhat.com> To: kvmarm@lists.cs.columbia.edu Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, james.morse@arm.com, mark.rutland@arm.com, Jonathan.Cameron@huawei.com, will@kernel.org, maz@kernel.org, pbonzini@redhat.com, vkuznets@redhat.com, shan.gavin@gmail.com Subject: [PATCH v4 03/15] KVM: async_pf: Make GFN slot management generic Date: Sun, 15 Aug 2021 08:59:35 +0800 [thread overview] Message-ID: <20210815005947.83699-4-gshan@redhat.com> (raw) In-Reply-To: <20210815005947.83699-1-gshan@redhat.com> It's not allowed to fire duplicate notification for same GFN on x86 platform, with help of a hash table. This mechanism is going to be used by arm64 and this makes the code generic and shareable by multiple platforms. * As this mechanism isn't needed by all platforms, a new kernel config option (CONFIG_ASYNC_PF_SLOT) is introduced so that it can be disabled at compiling time. * The code is basically copied from x86 platform and the functions are renamed to reflect the fact: (a) the input parameters are vCPU and GFN. (b) The operations are resetting, searching, adding and removing. * Helper stub is also added on !CONFIG_KVM_ASYNC_PF because we're going to use IS_ENABLED() instead of #ifdef on arm64 when the asynchronous page fault is supported. This is preparatory work to use the newly introduced functions on x86 platform and arm64 in subsequent patches. Signed-off-by: Gavin Shan <gshan@redhat.com> --- include/linux/kvm_host.h | 18 +++++++++ virt/kvm/Kconfig | 3 ++ virt/kvm/async_pf.c | 85 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 106 insertions(+) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index a5f990f6dc35..a9685c2b2250 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -298,6 +298,9 @@ struct kvm_vcpu { #ifdef CONFIG_KVM_ASYNC_PF struct { +#ifdef CONFIG_KVM_ASYNC_PF_SLOT + gfn_t gfns[ASYNC_PF_PER_VCPU]; +#endif u32 queued; struct list_head queue; struct list_head done; @@ -339,6 +342,13 @@ struct kvm_async_pf { bool notpresent_injected; }; +#ifdef CONFIG_KVM_ASYNC_PF_SLOT +void kvm_async_pf_reset_slot(struct kvm_vcpu *vcpu); +void kvm_async_pf_add_slot(struct kvm_vcpu *vcpu, gfn_t gfn); +void kvm_async_pf_remove_slot(struct kvm_vcpu *vcpu, gfn_t gfn); +bool kvm_async_pf_find_slot(struct kvm_vcpu *vcpu, gfn_t gfn); +#endif + static inline bool kvm_check_async_pf_completion_queue(struct kvm_vcpu *vcpu) { return !list_empty_careful(&vcpu->async_pf.done); @@ -350,6 +360,14 @@ bool kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, unsigned long hva, struct kvm_arch_async_pf *arch); int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu); #else +static inline void kvm_async_pf_reset_slot(struct kvm_vcpu *vcpu) { } +static inline void kvm_async_pf_add_slot(struct kvm_vcpu *vcpu, gfn_t gfn) { } +static inline void kvm_async_pf_remove_slot(struct kvm_vcpu *vcpu, gfn_t gfn) { } +static inline bool kvm_async_pf_find_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + return false; +} + static inline bool kvm_check_async_pf_completion_queue(struct kvm_vcpu *vcpu) { return false; diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 62b39149b8c8..59b518c8c205 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -23,6 +23,9 @@ config KVM_MMIO config KVM_ASYNC_PF bool +config KVM_ASYNC_PF_SLOT + bool + # Toggle to switch between direct notification and batch job config KVM_ASYNC_PF_SYNC bool diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index d145a61a046a..0d1fdb2932af 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -13,12 +13,97 @@ #include <linux/module.h> #include <linux/mmu_context.h> #include <linux/sched/mm.h> +#ifdef CONFIG_KVM_ASYNC_PF_SLOT +#include <linux/hash.h> +#endif #include "async_pf.h" #include <trace/events/kvm.h> static struct kmem_cache *async_pf_cache; +#ifdef CONFIG_KVM_ASYNC_PF_SLOT +static inline u32 kvm_async_pf_hash(gfn_t gfn) +{ + BUILD_BUG_ON(!is_power_of_2(ASYNC_PF_PER_VCPU)); + + return hash_32(gfn & 0xffffffff, order_base_2(ASYNC_PF_PER_VCPU)); +} + +static inline u32 kvm_async_pf_next_slot(u32 key) +{ + return (key + 1) & (ASYNC_PF_PER_VCPU - 1); +} + +static u32 kvm_async_pf_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + u32 key = kvm_async_pf_hash(gfn); + int i; + + for (i = 0; i < ASYNC_PF_PER_VCPU && + (vcpu->async_pf.gfns[key] != gfn && + vcpu->async_pf.gfns[key] != ~0); i++) + key = kvm_async_pf_next_slot(key); + + return key; +} + +void kvm_async_pf_reset_slot(struct kvm_vcpu *vcpu) +{ + int i; + + for (i = 0; i < ASYNC_PF_PER_VCPU; i++) + vcpu->async_pf.gfns[i] = ~0; +} + +void kvm_async_pf_add_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + u32 key = kvm_async_pf_hash(gfn); + + while (vcpu->async_pf.gfns[key] != ~0) + key = kvm_async_pf_next_slot(key); + + vcpu->async_pf.gfns[key] = gfn; +} + +void kvm_async_pf_remove_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + u32 i, j, k; + + i = j = kvm_async_pf_slot(vcpu, gfn); + + if (WARN_ON_ONCE(vcpu->async_pf.gfns[i] != gfn)) + return; + + while (true) { + vcpu->async_pf.gfns[i] = ~0; + + do { + j = kvm_async_pf_next_slot(j); + if (vcpu->async_pf.gfns[j] == ~0) + return; + + k = kvm_async_pf_hash(vcpu->async_pf.gfns[j]); + /* + * k lies cyclically in ]i,j] + * | i.k.j | + * |....j i.k.| or |.k..j i...| + */ + } while ((i <= j) ? (i < k && k <= j) : (i < k || k <= j)); + + vcpu->async_pf.gfns[i] = vcpu->async_pf.gfns[j]; + i = j; + } +} + +bool kvm_async_pf_find_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + u32 key = kvm_async_pf_slot(vcpu, gfn); + + return vcpu->async_pf.gfns[key] == gfn; +} +#endif /* CONFIG_KVM_ASYNC_PF_SLOT */ + int kvm_async_pf_init(void) { async_pf_cache = KMEM_CACHE(kvm_async_pf, 0); -- 2.23.0
WARNING: multiple messages have this Message-ID (diff)
From: Gavin Shan <gshan@redhat.com> To: kvmarm@lists.cs.columbia.edu Cc: kvm@vger.kernel.org, maz@kernel.org, linux-kernel@vger.kernel.org, shan.gavin@gmail.com, Jonathan.Cameron@huawei.com, pbonzini@redhat.com, vkuznets@redhat.com, will@kernel.org Subject: [PATCH v4 03/15] KVM: async_pf: Make GFN slot management generic Date: Sun, 15 Aug 2021 08:59:35 +0800 [thread overview] Message-ID: <20210815005947.83699-4-gshan@redhat.com> (raw) In-Reply-To: <20210815005947.83699-1-gshan@redhat.com> It's not allowed to fire duplicate notification for same GFN on x86 platform, with help of a hash table. This mechanism is going to be used by arm64 and this makes the code generic and shareable by multiple platforms. * As this mechanism isn't needed by all platforms, a new kernel config option (CONFIG_ASYNC_PF_SLOT) is introduced so that it can be disabled at compiling time. * The code is basically copied from x86 platform and the functions are renamed to reflect the fact: (a) the input parameters are vCPU and GFN. (b) The operations are resetting, searching, adding and removing. * Helper stub is also added on !CONFIG_KVM_ASYNC_PF because we're going to use IS_ENABLED() instead of #ifdef on arm64 when the asynchronous page fault is supported. This is preparatory work to use the newly introduced functions on x86 platform and arm64 in subsequent patches. Signed-off-by: Gavin Shan <gshan@redhat.com> --- include/linux/kvm_host.h | 18 +++++++++ virt/kvm/Kconfig | 3 ++ virt/kvm/async_pf.c | 85 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 106 insertions(+) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index a5f990f6dc35..a9685c2b2250 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -298,6 +298,9 @@ struct kvm_vcpu { #ifdef CONFIG_KVM_ASYNC_PF struct { +#ifdef CONFIG_KVM_ASYNC_PF_SLOT + gfn_t gfns[ASYNC_PF_PER_VCPU]; +#endif u32 queued; struct list_head queue; struct list_head done; @@ -339,6 +342,13 @@ struct kvm_async_pf { bool notpresent_injected; }; +#ifdef CONFIG_KVM_ASYNC_PF_SLOT +void kvm_async_pf_reset_slot(struct kvm_vcpu *vcpu); +void kvm_async_pf_add_slot(struct kvm_vcpu *vcpu, gfn_t gfn); +void kvm_async_pf_remove_slot(struct kvm_vcpu *vcpu, gfn_t gfn); +bool kvm_async_pf_find_slot(struct kvm_vcpu *vcpu, gfn_t gfn); +#endif + static inline bool kvm_check_async_pf_completion_queue(struct kvm_vcpu *vcpu) { return !list_empty_careful(&vcpu->async_pf.done); @@ -350,6 +360,14 @@ bool kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, unsigned long hva, struct kvm_arch_async_pf *arch); int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu); #else +static inline void kvm_async_pf_reset_slot(struct kvm_vcpu *vcpu) { } +static inline void kvm_async_pf_add_slot(struct kvm_vcpu *vcpu, gfn_t gfn) { } +static inline void kvm_async_pf_remove_slot(struct kvm_vcpu *vcpu, gfn_t gfn) { } +static inline bool kvm_async_pf_find_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + return false; +} + static inline bool kvm_check_async_pf_completion_queue(struct kvm_vcpu *vcpu) { return false; diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 62b39149b8c8..59b518c8c205 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -23,6 +23,9 @@ config KVM_MMIO config KVM_ASYNC_PF bool +config KVM_ASYNC_PF_SLOT + bool + # Toggle to switch between direct notification and batch job config KVM_ASYNC_PF_SYNC bool diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index d145a61a046a..0d1fdb2932af 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -13,12 +13,97 @@ #include <linux/module.h> #include <linux/mmu_context.h> #include <linux/sched/mm.h> +#ifdef CONFIG_KVM_ASYNC_PF_SLOT +#include <linux/hash.h> +#endif #include "async_pf.h" #include <trace/events/kvm.h> static struct kmem_cache *async_pf_cache; +#ifdef CONFIG_KVM_ASYNC_PF_SLOT +static inline u32 kvm_async_pf_hash(gfn_t gfn) +{ + BUILD_BUG_ON(!is_power_of_2(ASYNC_PF_PER_VCPU)); + + return hash_32(gfn & 0xffffffff, order_base_2(ASYNC_PF_PER_VCPU)); +} + +static inline u32 kvm_async_pf_next_slot(u32 key) +{ + return (key + 1) & (ASYNC_PF_PER_VCPU - 1); +} + +static u32 kvm_async_pf_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + u32 key = kvm_async_pf_hash(gfn); + int i; + + for (i = 0; i < ASYNC_PF_PER_VCPU && + (vcpu->async_pf.gfns[key] != gfn && + vcpu->async_pf.gfns[key] != ~0); i++) + key = kvm_async_pf_next_slot(key); + + return key; +} + +void kvm_async_pf_reset_slot(struct kvm_vcpu *vcpu) +{ + int i; + + for (i = 0; i < ASYNC_PF_PER_VCPU; i++) + vcpu->async_pf.gfns[i] = ~0; +} + +void kvm_async_pf_add_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + u32 key = kvm_async_pf_hash(gfn); + + while (vcpu->async_pf.gfns[key] != ~0) + key = kvm_async_pf_next_slot(key); + + vcpu->async_pf.gfns[key] = gfn; +} + +void kvm_async_pf_remove_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + u32 i, j, k; + + i = j = kvm_async_pf_slot(vcpu, gfn); + + if (WARN_ON_ONCE(vcpu->async_pf.gfns[i] != gfn)) + return; + + while (true) { + vcpu->async_pf.gfns[i] = ~0; + + do { + j = kvm_async_pf_next_slot(j); + if (vcpu->async_pf.gfns[j] == ~0) + return; + + k = kvm_async_pf_hash(vcpu->async_pf.gfns[j]); + /* + * k lies cyclically in ]i,j] + * | i.k.j | + * |....j i.k.| or |.k..j i...| + */ + } while ((i <= j) ? (i < k && k <= j) : (i < k || k <= j)); + + vcpu->async_pf.gfns[i] = vcpu->async_pf.gfns[j]; + i = j; + } +} + +bool kvm_async_pf_find_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + u32 key = kvm_async_pf_slot(vcpu, gfn); + + return vcpu->async_pf.gfns[key] == gfn; +} +#endif /* CONFIG_KVM_ASYNC_PF_SLOT */ + int kvm_async_pf_init(void) { async_pf_cache = KMEM_CACHE(kvm_async_pf, 0); -- 2.23.0 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
next prev parent reply other threads:[~2021-08-15 1:02 UTC|newest] Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-15 0:59 [PATCH v4 00/15] Support Asynchronous Page Fault Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 01/15] KVM: async_pf: Move struct kvm_async_pf around Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-11-10 15:37 ` Eric Auger 2021-11-10 15:37 ` Eric Auger 2022-01-13 7:21 ` Gavin Shan 2022-01-13 7:21 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 02/15] KVM: async_pf: Add helper function to check completion queue Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-08-16 16:53 ` Vitaly Kuznetsov 2021-08-16 16:53 ` Vitaly Kuznetsov 2021-08-17 10:44 ` Gavin Shan 2021-08-17 10:44 ` Gavin Shan 2021-11-10 15:37 ` Eric Auger 2021-11-10 15:37 ` Eric Auger 2022-01-13 7:38 ` Gavin Shan 2022-01-13 7:38 ` Gavin Shan 2021-08-15 0:59 ` Gavin Shan [this message] 2021-08-15 0:59 ` [PATCH v4 03/15] KVM: async_pf: Make GFN slot management generic Gavin Shan 2021-11-10 17:00 ` Eric Auger 2021-11-10 17:00 ` Eric Auger 2022-01-13 7:42 ` Gavin Shan 2022-01-13 7:42 ` Gavin Shan 2021-11-10 17:00 ` Eric Auger 2021-11-10 17:00 ` Eric Auger 2021-08-15 0:59 ` [PATCH v4 04/15] KVM: x86: Use generic async PF slot management Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-11-10 17:03 ` Eric Auger 2021-11-10 17:03 ` Eric Auger 2022-01-13 7:44 ` Gavin Shan 2022-01-13 7:44 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 05/15] KVM: arm64: Export kvm_handle_user_mem_abort() Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-11-10 18:02 ` Eric Auger 2021-11-10 18:02 ` Eric Auger 2022-01-13 7:55 ` Gavin Shan 2022-01-13 7:55 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 06/15] KVM: arm64: Add paravirtualization header files Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-11-10 18:06 ` Eric Auger 2021-11-10 18:06 ` Eric Auger 2022-01-13 8:00 ` Gavin Shan 2022-01-13 8:00 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 07/15] KVM: arm64: Support page-not-present notification Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-11-12 15:01 ` Eric Auger 2021-11-12 15:01 ` Eric Auger 2022-01-13 8:43 ` Gavin Shan 2022-01-13 8:43 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 08/15] KVM: arm64: Support page-ready notification Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 09/15] KVM: arm64: Support async PF hypercalls Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 10/15] KVM: arm64: Support async PF ioctl commands Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 11/15] KVM: arm64: Export async PF capability Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 12/15] arm64: Detect async PF para-virtualization feature Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 13/15] arm64: Reschedule process on aync PF Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 14/15] arm64: Enable async PF Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-08-16 17:05 ` Vitaly Kuznetsov 2021-08-16 17:05 ` Vitaly Kuznetsov 2021-08-17 10:49 ` Gavin Shan 2021-08-17 10:49 ` Gavin Shan 2021-08-15 0:59 ` [PATCH v4 15/15] KVM: arm64: Add async PF document Gavin Shan 2021-08-15 0:59 ` Gavin Shan 2021-11-11 10:39 ` Eric Auger 2021-11-11 10:39 ` Eric Auger
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