arm64: KVM: allow export and import of generic timer regs

For correct guest suspend/resume behaviour we need to ensure we include
the generic timer registers for 64 bit guests. As CONFIG_KVM_ARM_TIMER is
always set for arm64 we don't need to worry about null implementations.
However I have re-jigged the kvm_arm_timer_set/get_reg declarations to
be in the common include/kvm/arm_arch_timer.h headers.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 67 insertions, 1 deletions

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 60b5c31f3c10..8d1ec2887a26 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -136,13 +136,67 @@ static unsigned long num_core_regs(void)
 }
 
 /**
+ * ARM64 versions of the TIMER registers, always available on arm64
+ */
+
+#define NUM_TIMER_REGS 3
+
+static bool is_timer_reg(u64 index)
+{
+        switch (index) {
+        case KVM_REG_ARM_TIMER_CTL:
+        case KVM_REG_ARM_TIMER_CNT:
+        case KVM_REG_ARM_TIMER_CVAL:
+                return true;
+        }
+        return false;
+}
+
+static int copy_timer_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
+{
+        if (put_user(KVM_REG_ARM_TIMER_CTL, uindices))
+                return -EFAULT;
+        uindices++;
+        if (put_user(KVM_REG_ARM_TIMER_CNT, uindices))
+                return -EFAULT;
+        uindices++;
+        if (put_user(KVM_REG_ARM_TIMER_CVAL, uindices))
+                return -EFAULT;
+
+        return 0;
+}
+
+static int set_timer_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+        void __user *uaddr = (void __user *)(long)reg->addr;
+        u64 val;
+        int ret;
+
+        ret = copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id));
+        if (ret != 0)
+                return ret;
+
+        return kvm_arm_timer_set_reg(vcpu, reg->id, val);
+}
+
+static int get_timer_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+        void __user *uaddr = (void __user *)(long)reg->addr;
+        u64 val;
+
+        val = kvm_arm_timer_get_reg(vcpu, reg->id);
+        return copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id));
+}
+
+/**
  * kvm_arm_num_regs - how many registers do we present via KVM_GET_ONE_REG
  *
  * This is for all registers.
  */
 unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
 {
-        return num_core_regs() + kvm_arm_num_sys_reg_descs(vcpu);
+        return num_core_regs() + kvm_arm_num_sys_reg_descs(vcpu)
+                + NUM_TIMER_REGS;
 }
 
 /**
@@ -154,6 +208,7 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
 {
         unsigned int i;
         const u64 core_reg = KVM_REG_ARM64 | KVM_REG_SIZE_U64 | KVM_REG_ARM_CORE;
+        int ret;
 
         for (i = 0; i < sizeof(struct kvm_regs) / sizeof(__u32); i++) {
                 if (put_user(core_reg | i, uindices))
@@ -161,6 +216,11 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
                 uindices++;
         }
 
+        ret = copy_timer_indices(vcpu, uindices);
+        if (ret)
+                return ret;
+        uindices += NUM_TIMER_REGS;
+
         return kvm_arm_copy_sys_reg_indices(vcpu, uindices);
 }
 
@@ -174,6 +234,9 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
         if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE)
                 return get_core_reg(vcpu, reg);
 
+        if (is_timer_reg(reg->id))
+                return get_timer_reg(vcpu, reg);
+
         return kvm_arm_sys_reg_get_reg(vcpu, reg);
 }
 
@@ -187,6 +250,9 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
         if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE)
                 return set_core_reg(vcpu, reg);
 
+        if (is_timer_reg(reg->id))
+                return set_timer_reg(vcpu, reg);
+
         return kvm_arm_sys_reg_set_reg(vcpu, reg);
 }