2014-07-04 14:54:01

by Alex Bennée

[permalink] [raw]
Subject: [PATCH] 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.

Signed-off-by: Alex Bennée <[email protected]>
---
arch/arm/include/asm/kvm_host.h | 3 --
arch/arm/kvm/guest.c | 10 ------
arch/arm64/kvm/guest.c | 68 ++++++++++++++++++++++++++++++++++++++++-
include/kvm/arm_arch_timer.h | 14 +++++++++
4 files changed, 81 insertions(+), 14 deletions(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 09af149..bce6d32 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -228,7 +228,4 @@ static inline int kvm_arch_dev_ioctl_check_extension(long ext)
int kvm_perf_init(void);
int kvm_perf_teardown(void);

-u64 kvm_arm_timer_get_reg(struct kvm_vcpu *, u64 regid);
-int kvm_arm_timer_set_reg(struct kvm_vcpu *, u64 regid, u64 value);
-
#endif /* __ARM_KVM_HOST_H__ */
diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c
index b23a59c..986e625 100644
--- a/arch/arm/kvm/guest.c
+++ b/arch/arm/kvm/guest.c
@@ -124,16 +124,6 @@ static bool is_timer_reg(u64 index)
return false;
}

-int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value)
-{
- return 0;
-}
-
-u64 kvm_arm_timer_get_reg(struct kvm_vcpu *vcpu, u64 regid)
-{
- return 0;
-}
-
#else

#define NUM_TIMER_REGS 3
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 0874557..205f0d8 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);
}

diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index 6d9aedd..ad9db60 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -67,6 +67,10 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu);
void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu);
void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu);
void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu);
+
+u64 kvm_arm_timer_get_reg(struct kvm_vcpu *, u64 regid);
+int kvm_arm_timer_set_reg(struct kvm_vcpu *, u64 regid, u64 value);
+
#else
static inline int kvm_timer_hyp_init(void)
{
@@ -84,6 +88,16 @@ static inline void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) {}
static inline void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu) {}
static inline void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu) {}
static inline void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu) {}
+
+static inline int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value)
+{
+ return 0;
+}
+
+static inline u64 kvm_arm_timer_get_reg(struct kvm_vcpu *vcpu, u64 regid)
+{
+ return 0;
+}
#endif

#endif
--
2.0.1


2014-07-07 07:30:59

by Marc Zyngier

[permalink] [raw]
Subject: Re: [PATCH] arm64: KVM: allow export and import of generic timer regs

On Fri, Jul 04 2014 at 3:54:14 pm BST, Alex Bennée <[email protected]> wrote:
> 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.
>
> Signed-off-by: Alex Bennée <[email protected]>

Acked-by: Marc Zyngier <[email protected]>

M.
--
Without deviation from the norm, progress is not possible.

2014-07-07 08:49:39

by Christoffer Dall

[permalink] [raw]
Subject: Re: [PATCH] arm64: KVM: allow export and import of generic timer regs

On Fri, Jul 04, 2014 at 03:54:14PM +0100, Alex Benn?e wrote:
> 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.
>
> Signed-off-by: Alex Benn?e <[email protected]>

Reviewed-by: Christoffer Dall <[email protected]>