[PATCH v5] ARM/KVM: save and restore generic timer registers
Christoffer Dall
christoffer.dall at linaro.org
Fri Dec 13 16:13:08 EST 2013
On Fri, Dec 13, 2013 at 09:35:49PM +0100, Andre Przywara wrote:
> On 12/13/2013 09:10 PM, Christoffer Dall wrote:
> >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?
>
> Currently not at all. Sorry if there was a misunderstanding
> regarding this. I don't have the hardware to test this, so I just
> did the 32-bit part. The 64-bit pieces were just to make it
> _compile_ on 64-bit, which is needed because of shared code in the
> arch_timer area.
> See Marc's comment here:
> https://lists.cs.columbia.edu/pipermail/kvmarm/2013-June/006133.html
>
ok, that's fine, I didn't test save/restore on arm64 yet either. We can
add it later.
Otherwise the patch looks good!
Acked-by: Christoffer Dall <christoffer.dall at linaro.org>
Thanks,
-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
> >>
>
--
Christoffer
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