[PATCH v5] ARM/KVM: save and restore generic timer registers
Christoffer Dall
christoffer.dall at linaro.org
Fri Dec 13 15:10:17 EST 2013
On Fri, Dec 13, 2013 at 02:23:26PM +0100, Andre Przywara wrote:
> For migration to work we need to save (and later restore) the state of
> each core's virtual generic timer.
> Since this is per VCPU, we can use the [gs]et_one_reg ioctl and export
> the three needed registers (control, counter, compare value).
> Though they live in cp15 space, we don't use the existing list, since
> they need special accessor functions and the arch timer is optional.
>
> Signed-off-by: Andre Przywara <andre.przywara at linaro.org>
> Signed-off-by: Christoffer Dall <christoffer.dall at linaro.org>
> ---
> Changes from v1:
> - move code out of coproc.c and into guest.c and arch_timer.c
> - present the registers with their native CP15 addresses, but without
> using space in the VCPU's cp15 array
> - do the user space copying in the accessor functions
>
> Changes from v2:
> - fix compilation without CONFIG_ARCH_TIMER
> - fix compilation for arm64 by defining the appropriate registers there
> - move userspace access out of arch_timer.c into coproc.c
> - Christoffer: removed whitespace in function declaration
>
> Changes from v3:
> - adapted Marc's SYSREG macro magic from kvmtool for nicer looking code
>
> Changes from v4:
> - remove ARM64-REG32 type, the ARM ARM defines no 32-bit system registers
>
> arch/arm/include/asm/kvm_host.h | 3 ++
> arch/arm/include/uapi/asm/kvm.h | 20 +++++++++
> arch/arm/kvm/guest.c | 92 ++++++++++++++++++++++++++++++++++++++-
> arch/arm64/include/uapi/asm/kvm.h | 18 ++++++++
> virt/kvm/arm/arch_timer.c | 34 +++++++++++++++
> 5 files changed, 166 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index 8a6f6db..098f7dd 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -225,4 +225,7 @@ 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/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
> index c498b60..835b867 100644
> --- a/arch/arm/include/uapi/asm/kvm.h
> +++ b/arch/arm/include/uapi/asm/kvm.h
> @@ -119,6 +119,26 @@ struct kvm_arch_memory_slot {
> #define KVM_REG_ARM_32_CRN_MASK 0x0000000000007800
> #define KVM_REG_ARM_32_CRN_SHIFT 11
>
> +#define ARM_CP15_REG_SHIFT_MASK(x,n) \
> + (((x) << KVM_REG_ARM_ ## n ## _SHIFT) & KVM_REG_ARM_ ## n ## _MASK)
> +
> +#define __ARM_CP15_REG(op1,crn,crm,op2) \
> + (KVM_REG_ARM | (15 << KVM_REG_ARM_COPROC_SHIFT) | \
> + ARM_CP15_REG_SHIFT_MASK(op1, OPC1) | \
> + ARM_CP15_REG_SHIFT_MASK(crn, 32_CRN) | \
> + ARM_CP15_REG_SHIFT_MASK(crm, CRM) | \
> + ARM_CP15_REG_SHIFT_MASK(op2, 32_OPC2))
> +
> +#define ARM_CP15_REG32(...) (__ARM_CP15_REG(__VA_ARGS__) | KVM_REG_SIZE_U32)
> +
> +#define __ARM_CP15_REG64(op1,crm) \
> + (__ARM_CP15_REG(op1, 0, crm, 0) | KVM_REG_SIZE_U64)
> +#define ARM_CP15_REG64(...) __ARM_CP15_REG64(__VA_ARGS__)
> +
> +#define KVM_REG_ARM_TIMER_CTL ARM_CP15_REG32(0, 14, 3, 1)
> +#define KVM_REG_ARM_TIMER_CNT ARM_CP15_REG64(1, 14)
> +#define KVM_REG_ARM_TIMER_CVAL ARM_CP15_REG64(3, 14)
> +
> /* Normal registers are mapped as coprocessor 16. */
> #define KVM_REG_ARM_CORE (0x0010 << KVM_REG_ARM_COPROC_SHIFT)
> #define KVM_REG_ARM_CORE_REG(name) (offsetof(struct kvm_regs, name) / 4)
> diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c
> index 20f8d97..2786eae 100644
> --- a/arch/arm/kvm/guest.c
> +++ b/arch/arm/kvm/guest.c
> @@ -109,6 +109,83 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
> return -EINVAL;
> }
>
> +#ifndef CONFIG_KVM_ARM_TIMER
> +
> +#define NUM_TIMER_REGS 0
> +
> +static int copy_timer_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
> +{
> + return 0;
> +}
> +
> +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
> +
> +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;
> +}
> +
> +#endif
> +
> +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));
> +}
> +
how does any of this code get called for arm64?
-Christoffer
> static unsigned long num_core_regs(void)
> {
> return sizeof(struct kvm_regs) / sizeof(u32);
> @@ -121,7 +198,8 @@ static unsigned long num_core_regs(void)
> */
> unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
> {
> - return num_core_regs() + kvm_arm_num_coproc_regs(vcpu);
> + return num_core_regs() + kvm_arm_num_coproc_regs(vcpu)
> + + NUM_TIMER_REGS;
> }
>
> /**
> @@ -133,6 +211,7 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
> {
> unsigned int i;
> const u64 core_reg = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_CORE;
> + int ret;
>
> for (i = 0; i < sizeof(struct kvm_regs)/sizeof(u32); i++) {
> if (put_user(core_reg | i, uindices))
> @@ -140,6 +219,11 @@ 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_coproc_indices(vcpu, uindices);
> }
>
> @@ -153,6 +237,9 @@ 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_coproc_get_reg(vcpu, reg);
> }
>
> @@ -166,6 +253,9 @@ 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_coproc_set_reg(vcpu, reg);
> }
>
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 5031f42..7c25ca8 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -129,6 +129,24 @@ struct kvm_arch_memory_slot {
> #define KVM_REG_ARM64_SYSREG_OP2_MASK 0x0000000000000007
> #define KVM_REG_ARM64_SYSREG_OP2_SHIFT 0
>
> +#define ARM64_SYS_REG_SHIFT_MASK(x,n) \
> + (((x) << KVM_REG_ARM64_SYSREG_ ## n ## _SHIFT) & \
> + KVM_REG_ARM64_SYSREG_ ## n ## _MASK)
> +
> +#define __ARM64_SYS_REG(op0,op1,crn,crm,op2) \
> + (KVM_REG_ARM64 | KVM_REG_ARM64_SYSREG | \
> + ARM64_SYS_REG_SHIFT_MASK(op0, OP0) | \
> + ARM64_SYS_REG_SHIFT_MASK(op1, OP1) | \
> + ARM64_SYS_REG_SHIFT_MASK(crn, CRN) | \
> + ARM64_SYS_REG_SHIFT_MASK(crm, CRM) | \
> + ARM64_SYS_REG_SHIFT_MASK(op2, OP2))
> +
> +#define ARM64_SYS_REG(...) (__ARM64_SYS_REG(__VA_ARGS__) | KVM_REG_SIZE_U64)
> +
> +#define KVM_REG_ARM_TIMER_CTL ARM64_SYS_REG(3, 3, 14, 3, 1)
> +#define KVM_REG_ARM_TIMER_CNT ARM64_SYS_REG(3, 3, 14, 3, 2)
> +#define KVM_REG_ARM_TIMER_CVAL ARM64_SYS_REG(3, 3, 14, 0, 2)
> +
> /* KVM_IRQ_LINE irq field index values */
> #define KVM_ARM_IRQ_TYPE_SHIFT 24
> #define KVM_ARM_IRQ_TYPE_MASK 0xff
> diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
> index c2e1ef4..5081e80 100644
> --- a/virt/kvm/arm/arch_timer.c
> +++ b/virt/kvm/arm/arch_timer.c
> @@ -182,6 +182,40 @@ static void kvm_timer_init_interrupt(void *info)
> enable_percpu_irq(host_vtimer_irq, 0);
> }
>
> +int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value)
> +{
> + struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
> +
> + switch (regid) {
> + case KVM_REG_ARM_TIMER_CTL:
> + timer->cntv_ctl = value;
> + break;
> + case KVM_REG_ARM_TIMER_CNT:
> + vcpu->kvm->arch.timer.cntvoff = kvm_phys_timer_read() - value;
> + break;
> + case KVM_REG_ARM_TIMER_CVAL:
> + timer->cntv_cval = value;
> + break;
> + default:
> + return -1;
> + }
> + return 0;
> +}
> +
> +u64 kvm_arm_timer_get_reg(struct kvm_vcpu *vcpu, u64 regid)
> +{
> + struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
> +
> + switch (regid) {
> + case KVM_REG_ARM_TIMER_CTL:
> + return timer->cntv_ctl;
> + case KVM_REG_ARM_TIMER_CNT:
> + return kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
> + case KVM_REG_ARM_TIMER_CVAL:
> + return timer->cntv_cval;
> + }
> + return (u64)-1;
> +}
>
> static int kvm_timer_cpu_notify(struct notifier_block *self,
> unsigned long action, void *cpu)
> --
> 1.7.12.1
>
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