From cac0f1b7285eaaf9a186c618c3a7304d82ed5493 Mon Sep 17 00:00:00 2001 From: Steven Price Date: Mon, 21 Oct 2019 16:28:17 +0100 Subject: KVM: Implement kvm_put_guest() kvm_put_guest() is analogous to put_user() - it writes a single value to the guest physical address. The implementation is built upon put_user() and so it has the same single copy atomic properties. Signed-off-by: Steven Price Signed-off-by: Marc Zyngier --- include/linux/kvm_host.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 719fc3e15ea4..9907e45f8875 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -746,6 +746,28 @@ int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, unsigned long len); int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, gpa_t gpa, unsigned long len); + +#define __kvm_put_guest(kvm, gfn, offset, value, type) \ +({ \ + unsigned long __addr = gfn_to_hva(kvm, gfn); \ + type __user *__uaddr = (type __user *)(__addr + offset); \ + int __ret = -EFAULT; \ + \ + if (!kvm_is_error_hva(__addr)) \ + __ret = put_user(value, __uaddr); \ + if (!__ret) \ + mark_page_dirty(kvm, gfn); \ + __ret; \ +}) + +#define kvm_put_guest(kvm, gpa, value, type) \ +({ \ + gpa_t __gpa = gpa; \ + struct kvm *__kvm = kvm; \ + __kvm_put_guest(__kvm, __gpa >> PAGE_SHIFT, \ + offset_in_page(__gpa), (value), type); \ +}) + int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len); int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len); struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn); -- cgit v1.2.3 From 8538cb22bbce5a988671b68baf0b0f9e86ca1e87 Mon Sep 17 00:00:00 2001 From: Steven Price Date: Mon, 21 Oct 2019 16:28:19 +0100 Subject: KVM: Allow kvm_device_ops to be const Currently a kvm_device_ops structure cannot be const without triggering compiler warnings. However the structure doesn't need to be written to and, by marking it const, it can be read-only in memory. Add some more const keywords to allow this. Reviewed-by: Andrew Jones Signed-off-by: Steven Price Signed-off-by: Marc Zyngier --- include/linux/kvm_host.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 9907e45f8875..7a26d5513471 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1262,7 +1262,7 @@ extern unsigned int halt_poll_ns_grow_start; extern unsigned int halt_poll_ns_shrink; struct kvm_device { - struct kvm_device_ops *ops; + const struct kvm_device_ops *ops; struct kvm *kvm; void *private; struct list_head vm_node; @@ -1315,7 +1315,7 @@ struct kvm_device_ops { void kvm_device_get(struct kvm_device *dev); void kvm_device_put(struct kvm_device *dev); struct kvm_device *kvm_device_from_filp(struct file *filp); -int kvm_register_device_ops(struct kvm_device_ops *ops, u32 type); +int kvm_register_device_ops(const struct kvm_device_ops *ops, u32 type); void kvm_unregister_device_ops(u32 type); extern struct kvm_device_ops kvm_mpic_ops; -- cgit v1.2.3 From 78958563d8023db0c6d03a2fe2a64d79b47b4349 Mon Sep 17 00:00:00 2001 From: Aaron Lewis Date: Mon, 21 Oct 2019 16:30:22 -0700 Subject: KVM: x86: Remove unneeded kvm_vcpu variable, guest_xcr0_loaded The kvm_vcpu variable, guest_xcr0_loaded, is a waste of an 'int' and a conditional branch. VMX and SVM are the only users, and both unconditionally pair kvm_load_guest_xcr0() with kvm_put_guest_xcr0() making this check unnecessary. Without this variable, the predicates in kvm_load_guest_xcr0 and kvm_put_guest_xcr0 should match. Suggested-by: Sean Christopherson Reviewed-by: Jim Mattson Signed-off-by: Aaron Lewis Change-Id: I7b1eb9b62969d7bbb2850f27e42f863421641b23 Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 719fc3e15ea4..d2017302996c 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -278,7 +278,6 @@ struct kvm_vcpu { struct mutex mutex; struct kvm_run *run; - int guest_xcr0_loaded; struct swait_queue_head wq; struct pid __rcu *pid; int sigset_active; -- cgit v1.2.3 From 149487bdacde32f5a9a344a49533ae0772fb9db7 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Mon, 21 Oct 2019 15:58:42 -0700 Subject: KVM: Add separate helper for putting borrowed reference to kvm Add a new helper, kvm_put_kvm_no_destroy(), to handle putting a borrowed reference[*] to the VM when installing a new file descriptor fails. KVM expects the refcount to remain valid in this case, as the in-progress ioctl() has an explicit reference to the VM. The primary motiviation for the helper is to document that the 'kvm' pointer is still valid after putting the borrowed reference, e.g. to document that doing mutex(&kvm->lock) immediately after putting a ref to kvm isn't broken. [*] When exposing a new object to userspace via a file descriptor, e.g. a new vcpu, KVM grabs a reference to itself (the VM) prior to making the object visible to userspace to avoid prematurely freeing the VM in the scenario where userspace immediately closes file descriptor. Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index d2017302996c..a817e446c9aa 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -621,6 +621,7 @@ void kvm_exit(void); void kvm_get_kvm(struct kvm *kvm); void kvm_put_kvm(struct kvm *kvm); +void kvm_put_kvm_no_destroy(struct kvm *kvm); static inline struct kvm_memslots *__kvm_memslots(struct kvm *kvm, int as_id) { -- cgit v1.2.3 From 8750e72a79dda2f665ce17b62049f4d62130d991 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Date: Thu, 7 Nov 2019 07:53:42 -0500 Subject: KVM: remember position in kvm->vcpus array MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fetching an index for any vcpu in kvm->vcpus array by traversing the entire array everytime is costly. This patch remembers the position of each vcpu in kvm->vcpus array by storing it in vcpus_idx under kvm_vcpu structure. Signed-off-by: Radim Krčmář Signed-off-by: Nitesh Narayan Lal Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index a817e446c9aa..70b2296fb2ae 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -266,7 +266,8 @@ struct kvm_vcpu { struct preempt_notifier preempt_notifier; #endif int cpu; - int vcpu_id; + int vcpu_id; /* id given by userspace at creation */ + int vcpu_idx; /* index in kvm->vcpus array */ int srcu_idx; int mode; u64 requests; @@ -570,13 +571,7 @@ static inline struct kvm_vcpu *kvm_get_vcpu_by_id(struct kvm *kvm, int id) static inline int kvm_vcpu_get_idx(struct kvm_vcpu *vcpu) { - struct kvm_vcpu *tmp; - int idx; - - kvm_for_each_vcpu(idx, tmp, vcpu->kvm) - if (tmp == vcpu) - return idx; - BUG(); + return vcpu->vcpu_idx; } #define kvm_for_each_memslot(memslot, slots) \ -- cgit v1.2.3 From 7ee30bc132c683d06a6d9e360e39e483e3990708 Mon Sep 17 00:00:00 2001 From: Nitesh Narayan Lal Date: Thu, 7 Nov 2019 07:53:43 -0500 Subject: KVM: x86: deliver KVM IOAPIC scan request to target vCPUs In IOAPIC fixed delivery mode instead of flushing the scan requests to all vCPUs, we should only send the requests to vCPUs specified within the destination field. This patch introduces kvm_get_dest_vcpus_mask() API which retrieves an array of target vCPUs by using kvm_apic_map_get_dest_lapic() and then based on the vcpus_idx, it sets the bit in a bitmap. However, if the above fails kvm_get_dest_vcpus_mask() finds the target vCPUs by traversing all available vCPUs. Followed by setting the bits in the bitmap. If we had different vCPUs in the previous request for the same redirection table entry then bits corresponding to these vCPUs are also set. This to done to keep ioapic_handled_vectors synchronized. This bitmap is then eventually passed on to kvm_make_vcpus_request_mask() to generate a masked request only for the target vCPUs. This would enable us to reduce the latency overhead on isolated vCPUs caused by the IPI to process due to KVM_REQ_IOAPIC_SCAN. Suggested-by: Marcelo Tosatti Signed-off-by: Nitesh Narayan Lal Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 70b2296fb2ae..bfe6c6729988 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -786,6 +786,8 @@ void kvm_reload_remote_mmus(struct kvm *kvm); bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req, unsigned long *vcpu_bitmap, cpumask_var_t tmp); bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req); +bool kvm_make_cpus_request_mask(struct kvm *kvm, unsigned int req, + unsigned long *vcpu_bitmap); long kvm_arch_dev_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg); -- cgit v1.2.3