KVM: MIPS: Add vcpu_run() & vcpu_reenter() callbacks

Add implementation callbacks for entering the guest (vcpu_run()) and
reentering the guest (vcpu_reenter()), allowing implementation specific
operations to be performed before entering the guest or after returning
to the host without cluttering kvm_arch_vcpu_ioctl_run().

This allows the T&E specific lazy user GVA flush to be moved into
trap_emul.c, along with disabling of the HTW. We also move
kvm_mips_deliver_interrupts() as VZ will need to restore the guest timer
state prior to delivering interrupts.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

3 files changed, 52 insertions, 41 deletions

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 923f81dc6115..9f319375835a 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -539,6 +539,8 @@ struct kvm_mips_callbacks {
                            const struct kvm_one_reg *reg, s64 v);
         int (*vcpu_load)(struct kvm_vcpu *vcpu, int cpu);
         int (*vcpu_put)(struct kvm_vcpu *vcpu, int cpu);
+        int (*vcpu_run)(struct kvm_run *run, struct kvm_vcpu *vcpu);
+        void (*vcpu_reenter)(struct kvm_run *run, struct kvm_vcpu *vcpu);
 };
 extern struct kvm_mips_callbacks *kvm_mips_callbacks;
 int kvm_mips_emulation_init(struct kvm_mips_callbacks **install_callbacks);
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 85bc54f35695..1733877d8a53 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -410,32 +410,6 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
         return -ENOIOCTLCMD;
 }
 
-/* Must be called with preemption disabled, just before entering guest */
-static void kvm_mips_check_asids(struct kvm_vcpu *vcpu)
-{
-        struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;
-        struct mips_coproc *cop0 = vcpu->arch.cop0;
-        int i, cpu = smp_processor_id();
-        unsigned int gasid;
-
-        /*
-         * Lazy host ASID regeneration for guest user mode.
-         * If the guest ASID has changed since the last guest usermode
-         * execution, regenerate the host ASID so as to invalidate stale TLB
-         * entries.
-         */
-        if (!KVM_GUEST_KERNEL_MODE(vcpu)) {
-                gasid = kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID;
-                if (gasid != vcpu->arch.last_user_gasid) {
-                        kvm_get_new_mmu_context(user_mm, cpu, vcpu);
-                        for_each_possible_cpu(i)
-                                if (i != cpu)
-                                        cpu_context(i, user_mm) = 0;
-                        vcpu->arch.last_user_gasid = gasid;
-                }
-        }
-}
-
 int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 {
         int r = 0;
@@ -453,25 +427,12 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
         lose_fpu(1);
 
         local_irq_disable();
-        /* Check if we have any exceptions/interrupts pending */
-        kvm_mips_deliver_interrupts(vcpu,
-                                    kvm_read_c0_guest_cause(vcpu->arch.cop0));
-
         guest_enter_irqoff();
-
-        /* Disable hardware page table walking while in guest */
-        htw_stop();
-
         trace_kvm_enter(vcpu);
 
-        kvm_mips_check_asids(vcpu);
+        r = kvm_mips_callbacks->vcpu_run(run, vcpu);
 
-        r = vcpu->arch.vcpu_run(run, vcpu);
         trace_kvm_out(vcpu);
-
-        /* Re-enable HTW before enabling interrupts */
-        htw_start();
-
         guest_exit_irqoff();
         local_irq_enable();
 
@@ -1570,7 +1531,7 @@ skip_emul:
         if (ret == RESUME_GUEST) {
                 trace_kvm_reenter(vcpu);
 
-                kvm_mips_check_asids(vcpu);
+                kvm_mips_callbacks->vcpu_reenter(run, vcpu);
 
                 /*
                  * If FPU / MSA are enabled (i.e. the guest's FPU / MSA context
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index c7854d32fd64..92734d095c94 100644
--- a/arch/mips/kvm/trap_emul.c
+++ b/arch/mips/kvm/trap_emul.c
@@ -692,6 +692,52 @@ static int kvm_trap_emul_vcpu_put(struct kvm_vcpu *vcpu, int cpu)
         return 0;
 }
 
+static void kvm_trap_emul_vcpu_reenter(struct kvm_run *run,
+                                       struct kvm_vcpu *vcpu)
+{
+        struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;
+        struct mips_coproc *cop0 = vcpu->arch.cop0;
+        int i, cpu = smp_processor_id();
+        unsigned int gasid;
+
+        /*
+         * Lazy host ASID regeneration for guest user mode.
+         * If the guest ASID has changed since the last guest usermode
+         * execution, regenerate the host ASID so as to invalidate stale TLB
+         * entries.
+         */
+        if (!KVM_GUEST_KERNEL_MODE(vcpu)) {
+                gasid = kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID;
+                if (gasid != vcpu->arch.last_user_gasid) {
+                        kvm_get_new_mmu_context(user_mm, cpu, vcpu);
+                        for_each_possible_cpu(i)
+                                if (i != cpu)
+                                        cpu_context(i, user_mm) = 0;
+                        vcpu->arch.last_user_gasid = gasid;
+                }
+        }
+}
+
+static int kvm_trap_emul_vcpu_run(struct kvm_run *run, struct kvm_vcpu *vcpu)
+{
+        int r;
+
+        /* Check if we have any exceptions/interrupts pending */
+        kvm_mips_deliver_interrupts(vcpu,
+                                    kvm_read_c0_guest_cause(vcpu->arch.cop0));
+
+        kvm_trap_emul_vcpu_reenter(run, vcpu);
+
+        /* Disable hardware page table walking while in guest */
+        htw_stop();
+
+        r = vcpu->arch.vcpu_run(run, vcpu);
+
+        htw_start();
+
+        return r;
+}
+
 static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
         /* exit handlers */
         .handle_cop_unusable = kvm_trap_emul_handle_cop_unusable,
@@ -724,6 +770,8 @@ static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
         .set_one_reg = kvm_trap_emul_set_one_reg,
         .vcpu_load = kvm_trap_emul_vcpu_load,
         .vcpu_put = kvm_trap_emul_vcpu_put,
+        .vcpu_run = kvm_trap_emul_vcpu_run,
+        .vcpu_reenter = kvm_trap_emul_vcpu_reenter,
 };
 
 int kvm_mips_emulation_init(struct kvm_mips_callbacks **install_callbacks)