KVM: switch vcpu context to use SRCU

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

5 files changed, 43 insertions, 38 deletions

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index d0ad538f0083..d5e384641275 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -636,12 +636,9 @@ static void kvm_vcpu_post_transition(struct kvm_vcpu *vcpu)
 static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
         union context *host_ctx, *guest_ctx;
-        int r;
+        int r, idx;
 
-        /*
-         * down_read() may sleep and return with interrupts enabled
-         */
-        down_read(&vcpu->kvm->slots_lock);
+        idx = srcu_read_lock(&vcpu->kvm->srcu);
 
 again:
         if (signal_pending(current)) {
@@ -663,7 +660,7 @@ again:
         if (r < 0)
                 goto vcpu_run_fail;
 
-        up_read(&vcpu->kvm->slots_lock);
+        srcu_read_unlock(&vcpu->kvm->srcu, idx);
         kvm_guest_enter();
 
         /*
@@ -687,7 +684,7 @@ again:
         kvm_guest_exit();
         preempt_enable();
 
-        down_read(&vcpu->kvm->slots_lock);
+        idx = srcu_read_lock(&vcpu->kvm->srcu);
 
         r = kvm_handle_exit(kvm_run, vcpu);
 
@@ -697,10 +694,10 @@ again:
         }
 
 out:
-        up_read(&vcpu->kvm->slots_lock);
+        srcu_read_unlock(&vcpu->kvm->srcu, idx);
         if (r > 0) {
                 kvm_resched(vcpu);
-                down_read(&vcpu->kvm->slots_lock);
+                idx = srcu_read_lock(&vcpu->kvm->srcu);
                 goto again;
         }
 
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 06cce8285ba0..60f09ab3672c 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -67,10 +67,14 @@ static inline long kvm_s390_vcpu_get_memsize(struct kvm_vcpu *vcpu)
 
 static inline void kvm_s390_vcpu_set_mem(struct kvm_vcpu *vcpu)
 {
+        int idx;
         struct kvm_memory_slot *mem;
+        struct kvm_memslots *memslots;
 
-        down_read(&vcpu->kvm->slots_lock);
-        mem = &vcpu->kvm->memslots[0];
+        idx = srcu_read_lock(&vcpu->kvm->srcu);
+        memslots = rcu_dereference(vcpu->kvm->memslots);
+
+        mem = &memslots->memslots[0];
 
         vcpu->arch.sie_block->gmsor = mem->userspace_addr;
         vcpu->arch.sie_block->gmslm =
@@ -78,7 +82,7 @@ static inline void kvm_s390_vcpu_set_mem(struct kvm_vcpu *vcpu)
                 (mem->npages << PAGE_SHIFT) +
                 VIRTIODESCSPACE - 1ul;
 
-        up_read(&vcpu->kvm->slots_lock);
+        srcu_read_unlock(&vcpu->kvm->srcu, idx);
 }
 
 /* implemented in priv.c */
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index f8bf42a25995..25aabd00aa01 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2933,10 +2933,9 @@ static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask)
         spin_lock(&kvm_lock);
 
         list_for_each_entry(kvm, &vm_list, vm_list) {
-                int npages;
+                int npages, idx;
 
-                if (!down_read_trylock(&kvm->slots_lock))
-                        continue;
+                idx = srcu_read_lock(&kvm->srcu);
                 spin_lock(&kvm->mmu_lock);
                 npages = kvm->arch.n_alloc_mmu_pages -
                          kvm->arch.n_free_mmu_pages;
@@ -2949,7 +2948,7 @@ static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask)
                 nr_to_scan--;
 
                 spin_unlock(&kvm->mmu_lock);
-                up_read(&kvm->slots_lock);
+                srcu_read_unlock(&kvm->srcu, idx);
         }
         if (kvm_freed)
                 list_move_tail(&kvm_freed->vm_list, &vm_list);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f1cae7d6113d..22ab7137d1d0 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2478,10 +2478,10 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
 {
         struct vcpu_vmx *vmx = to_vmx(vcpu);
         u64 msr;
-        int ret;
+        int ret, idx;
 
         vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP));
-        down_read(&vcpu->kvm->slots_lock);
+        idx = srcu_read_lock(&vcpu->kvm->srcu);
         if (!init_rmode(vmx->vcpu.kvm)) {
                 ret = -ENOMEM;
                 goto out;
@@ -2589,7 +2589,7 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
         vmx->emulation_required = 0;
 
 out:
-        up_read(&vcpu->kvm->slots_lock);
+        srcu_read_unlock(&vcpu->kvm->srcu, idx);
         return ret;
 }
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9b42673df4af..53bc06a68105 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1306,15 +1306,15 @@ static int __msr_io(struct kvm_vcpu *vcpu, struct kvm_msrs *msrs,
                     int (*do_msr)(struct kvm_vcpu *vcpu,
                                   unsigned index, u64 *data))
 {
-        int i;
+        int i, idx;
 
         vcpu_load(vcpu);
 
-        down_read(&vcpu->kvm->slots_lock);
+        idx = srcu_read_lock(&vcpu->kvm->srcu);
         for (i = 0; i < msrs->nmsrs; ++i)
                 if (do_msr(vcpu, entries[i].index, &entries[i].data))
                         break;
-        up_read(&vcpu->kvm->slots_lock);
+        srcu_read_unlock(&vcpu->kvm->srcu, idx);
 
         vcpu_put(vcpu);
 
@@ -3900,14 +3900,15 @@ static void vapic_enter(struct kvm_vcpu *vcpu)
 static void vapic_exit(struct kvm_vcpu *vcpu)
 {
         struct kvm_lapic *apic = vcpu->arch.apic;
+        int idx;
 
         if (!apic || !apic->vapic_addr)
                 return;
 
-        down_read(&vcpu->kvm->slots_lock);
+        idx = srcu_read_lock(&vcpu->kvm->srcu);
         kvm_release_page_dirty(apic->vapic_page);
         mark_page_dirty(vcpu->kvm, apic->vapic_addr >> PAGE_SHIFT);
-        up_read(&vcpu->kvm->slots_lock);
+        srcu_read_unlock(&vcpu->kvm->srcu, idx);
 }
 
 static void update_cr8_intercept(struct kvm_vcpu *vcpu)
@@ -4036,7 +4037,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
                 kvm_lapic_sync_to_vapic(vcpu);
         }
 
-        up_read(&vcpu->kvm->slots_lock);
+        srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
 
         kvm_guest_enter();
 
@@ -4078,7 +4079,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 
         preempt_enable();
 
-        down_read(&vcpu->kvm->slots_lock);
+        vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
 
         /*
          * Profile KVM exit RIPs:
@@ -4100,6 +4101,7 @@ out:
 static int __vcpu_run(struct kvm_vcpu *vcpu)
 {
         int r;
+        struct kvm *kvm = vcpu->kvm;
 
         if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_SIPI_RECEIVED)) {
                 pr_debug("vcpu %d received sipi with vector # %x\n",
@@ -4111,7 +4113,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
                 vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
         }
 
-        down_read(&vcpu->kvm->slots_lock);
+        vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
         vapic_enter(vcpu);
 
         r = 1;
@@ -4119,9 +4121,9 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
                 if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE)
                         r = vcpu_enter_guest(vcpu);
                 else {
-                        up_read(&vcpu->kvm->slots_lock);
+                        srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
                         kvm_vcpu_block(vcpu);
-                        down_read(&vcpu->kvm->slots_lock);
+                        vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
                         if (test_and_clear_bit(KVM_REQ_UNHALT, &vcpu->requests))
                         {
                                 switch(vcpu->arch.mp_state) {
@@ -4156,13 +4158,13 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
                         ++vcpu->stat.signal_exits;
                 }
                 if (need_resched()) {
-                        up_read(&vcpu->kvm->slots_lock);
+                        srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
                         kvm_resched(vcpu);
-                        down_read(&vcpu->kvm->slots_lock);
+                        vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
                 }
         }
 
-        up_read(&vcpu->kvm->slots_lock);
+        srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
         post_kvm_run_save(vcpu);
 
         vapic_exit(vcpu);
@@ -4201,10 +4203,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                 vcpu->mmio_read_completed = 1;
                 vcpu->mmio_needed = 0;
 
-                down_read(&vcpu->kvm->slots_lock);
+                vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
                 r = emulate_instruction(vcpu, vcpu->arch.mmio_fault_cr2, 0,
                                         EMULTYPE_NO_DECODE);
-                up_read(&vcpu->kvm->slots_lock);
+                srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
                 if (r == EMULATE_DO_MMIO) {
                         /*
                          * Read-modify-write.  Back to userspace.
@@ -4967,11 +4969,12 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
 {
         unsigned long vaddr = tr->linear_address;
         gpa_t gpa;
+        int idx;
 
         vcpu_load(vcpu);
-        down_read(&vcpu->kvm->slots_lock);
+        idx = srcu_read_lock(&vcpu->kvm->srcu);
         gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, vaddr);
-        up_read(&vcpu->kvm->slots_lock);
+        srcu_read_unlock(&vcpu->kvm->srcu, idx);
         tr->physical_address = gpa;
         tr->valid = gpa != UNMAPPED_GVA;
         tr->writeable = 1;
@@ -5223,11 +5226,13 @@ fail:
 
 void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
 {
+        int idx;
+
         kfree(vcpu->arch.mce_banks);
         kvm_free_lapic(vcpu);
-        down_read(&vcpu->kvm->slots_lock);
+        idx = srcu_read_lock(&vcpu->kvm->srcu);
         kvm_mmu_destroy(vcpu);
-        up_read(&vcpu->kvm->slots_lock);
+        srcu_read_unlock(&vcpu->kvm->srcu, idx);
         free_page((unsigned long)vcpu->arch.pio_data);
 }