[PATCH 25/26] KVM: arm64: timers: Move timer registers to the sys_regs file

Marc Zyngier
2020-04-22T12:21:51Z

Move the timer gsisters to the sysreg file. This will further help when
they are directly changed by a nesting hypervisor in the VNCR page.

This requires moving the initialisation of the timer struct so that some
of the helpers (such as arch_timer_ctx_index) can work correctly at an
early stage.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/kvm_host.h | 6 ++
include/kvm/arm_arch_timer.h | 11 +--
virt/kvm/arm/arch_timer.c | 155 +++++++++++++++++++++++-------
virt/kvm/arm/trace.h | 8 +-
4 files changed, 136 insertions(+), 44 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index e8305761f0077..600dca55fc567 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -188,6 +188,12 @@ enum vcpu_sysreg {
SP_EL1,
SPSR_EL1,

+ CNTVOFF_EL2,
+ CNTV_CVAL_EL0,
+ CNTV_CTL_EL0,
+ CNTP_CVAL_EL0,
+ CNTP_CTL_EL0,
+
/* 32bit specific registers. Keep them at the end of the range */
DACR32_EL2, /* Domain Access Control Register */
IFSR32_EL2, /* Instruction Fault Status Register */
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index a821dd1df0cfa..51c19381108cf 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -26,16 +26,9 @@ enum kvm_arch_timer_regs {
struct arch_timer_context {
struct kvm_vcpu *vcpu;

- /* Registers: control register, timer value */
- u32 cnt_ctl;
- u64 cnt_cval;
-
/* Timer IRQ */
struct kvm_irq_level irq;

- /* Virtual offset */
- u64 cntvoff;
-
/* Emulated Timer (may be unused) */
struct hrtimer hrtimer;

@@ -109,4 +102,8 @@ void kvm_arm_timer_write_sysreg(struct kvm_vcpu *vcpu,
enum kvm_arch_timer_regs treg,
u64 val);

+/* Needed for tracing */
+u32 timer_get_ctl(struct arch_timer_context *ctxt);
+u64 timer_get_cval(struct arch_timer_context *ctxt);
+
#endif
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 1961de8828ee9..78b8eca02312e 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -51,6 +51,93 @@ static u64 kvm_arm_timer_read(struct kvm_vcpu *vcpu,
struct arch_timer_context *timer,
enum kvm_arch_timer_regs treg);

+u32 timer_get_ctl(struct arch_timer_context *ctxt)
+{
+ struct kvm_vcpu *vcpu = ctxt->vcpu;
+
+ switch(arch_timer_ctx_index(ctxt)) {
+ case TIMER_VTIMER:
+ return __vcpu_sys_reg(vcpu, CNTV_CTL_EL0);
+ case TIMER_PTIMER:
+ return __vcpu_sys_reg(vcpu, CNTP_CTL_EL0);
+ default:
+ WARN_ON(1);
+ return 0;
+ }
+}
+
+u64 timer_get_cval(struct arch_timer_context *ctxt)
+{
+ struct kvm_vcpu *vcpu = ctxt->vcpu;
+
+ switch(arch_timer_ctx_index(ctxt)) {
+ case TIMER_VTIMER:
+ return __vcpu_sys_reg(vcpu, CNTV_CVAL_EL0);
+ case TIMER_PTIMER:
+ return __vcpu_sys_reg(vcpu, CNTP_CVAL_EL0);
+ default:
+ WARN_ON(1);
+ return 0;
+ }
+}
+
+static u64 timer_get_offset(struct arch_timer_context *ctxt)
+{
+ struct kvm_vcpu *vcpu = ctxt->vcpu;
+
+ switch(arch_timer_ctx_index(ctxt)) {
+ case TIMER_VTIMER:
+ return __vcpu_sys_reg(vcpu, CNTVOFF_EL2);
+ default:
+ return 0;
+ }
+}
+
+static void timer_set_ctl(struct arch_timer_context *ctxt, u32 ctl)
+{
+ struct kvm_vcpu *vcpu = ctxt->vcpu;
+
+ switch(arch_timer_ctx_index(ctxt)) {
+ case TIMER_VTIMER:
+ __vcpu_sys_reg(vcpu, CNTV_CTL_EL0) = ctl;
+ break;
+ case TIMER_PTIMER:
+ __vcpu_sys_reg(vcpu, CNTP_CTL_EL0) = ctl;
+ break;
+ default:
+ WARN_ON(1);
+ }
+}
+
+static void timer_set_cval(struct arch_timer_context *ctxt, u64 cval)
+{
+ struct kvm_vcpu *vcpu = ctxt->vcpu;
+
+ switch(arch_timer_ctx_index(ctxt)) {
+ case TIMER_VTIMER:
+ __vcpu_sys_reg(vcpu, CNTV_CVAL_EL0) = cval;
+ break;
+ case TIMER_PTIMER:
+ __vcpu_sys_reg(vcpu, CNTP_CVAL_EL0) = cval;
+ break;
+ default:
+ WARN_ON(1);
+ }
+}
+
+static void timer_set_offset(struct arch_timer_context *ctxt, u64 offset)
+{
+ struct kvm_vcpu *vcpu = ctxt->vcpu;
+
+ switch(arch_timer_ctx_index(ctxt)) {
+ case TIMER_VTIMER:
+ __vcpu_sys_reg(vcpu, CNTVOFF_EL2) = offset;
+ break;
+ default:
+ WARN(offset, "timer %ld\n", arch_timer_ctx_index(ctxt));
+ }
+}
+
u64 kvm_phys_timer_read(void)
{
return timecounter->cc->read(timecounter->cc);
@@ -124,8 +211,8 @@ static u64 kvm_timer_compute_delta(struct arch_timer_context *timer_ctx)
{
u64 cval, now;

- cval = timer_ctx->cnt_cval;
- now = kvm_phys_timer_read() - timer_ctx->cntvoff;
+ cval = timer_get_cval(timer_ctx);
+ now = kvm_phys_timer_read() - timer_get_offset(timer_ctx);

if (now < cval) {
u64 ns;
@@ -144,8 +231,8 @@ static bool kvm_timer_irq_can_fire(struct arch_timer_context *timer_ctx)
{
WARN_ON(timer_ctx && timer_ctx->loaded);
return timer_ctx &&
- !(timer_ctx->cnt_ctl & ARCH_TIMER_CTRL_IT_MASK) &&
- (timer_ctx->cnt_ctl & ARCH_TIMER_CTRL_ENABLE);
+ ((timer_get_ctl(timer_ctx) &
+ (ARCH_TIMER_CTRL_IT_MASK | ARCH_TIMER_CTRL_ENABLE)) == ARCH_TIMER_CTRL_ENABLE);
}

/*
@@ -256,8 +343,8 @@ static bool kvm_timer_should_fire(struct arch_timer_context *timer_ctx)
if (!kvm_timer_irq_can_fire(timer_ctx))
return false;

- cval = timer_ctx->cnt_cval;
- now = kvm_phys_timer_read() - timer_ctx->cntvoff;
+ cval = timer_get_cval(timer_ctx);
+ now = kvm_phys_timer_read() - timer_get_offset(timer_ctx);

return cval <= now;
}
@@ -350,8 +437,8 @@ static void timer_save_state(struct arch_timer_context *ctx)

switch (index) {
case TIMER_VTIMER:
- ctx->cnt_ctl = read_sysreg_el0(SYS_CNTV_CTL);
- ctx->cnt_cval = read_sysreg_el0(SYS_CNTV_CVAL);
+ timer_set_ctl(ctx, read_sysreg_el0(SYS_CNTV_CTL));
+ timer_set_cval(ctx, read_sysreg_el0(SYS_CNTV_CVAL));

/* Disable the timer */
write_sysreg_el0(0, SYS_CNTV_CTL);
@@ -359,8 +446,8 @@ static void timer_save_state(struct arch_timer_context *ctx)

break;
case TIMER_PTIMER:
- ctx->cnt_ctl = read_sysreg_el0(SYS_CNTP_CTL);
- ctx->cnt_cval = read_sysreg_el0(SYS_CNTP_CVAL);
+ timer_set_ctl(ctx, read_sysreg_el0(SYS_CNTP_CTL));
+ timer_set_cval(ctx, read_sysreg_el0(SYS_CNTP_CVAL));

/* Disable the timer */
write_sysreg_el0(0, SYS_CNTP_CTL);
@@ -429,14 +516,14 @@ static void timer_restore_state(struct arch_timer_context *ctx)

switch (index) {
case TIMER_VTIMER:
- write_sysreg_el0(ctx->cnt_cval, SYS_CNTV_CVAL);
+ write_sysreg_el0(timer_get_cval(ctx), SYS_CNTV_CVAL);
isb();
- write_sysreg_el0(ctx->cnt_ctl, SYS_CNTV_CTL);
+ write_sysreg_el0(timer_get_ctl(ctx), SYS_CNTV_CTL);
break;
case TIMER_PTIMER:
- write_sysreg_el0(ctx->cnt_cval, SYS_CNTP_CVAL);
+ write_sysreg_el0(timer_get_cval(ctx), SYS_CNTP_CVAL);
isb();
- write_sysreg_el0(ctx->cnt_ctl, SYS_CNTP_CTL);
+ write_sysreg_el0(timer_get_ctl(ctx), SYS_CNTP_CTL);
break;
case NR_KVM_TIMERS:
BUG();
@@ -538,7 +625,7 @@ void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu)
kvm_timer_vcpu_load_nogic(vcpu);
}

- set_cntvoff(map.direct_vtimer->cntvoff);
+ set_cntvoff(timer_get_offset(map.direct_vtimer));

kvm_timer_unblocking(vcpu);

@@ -648,8 +735,8 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu)
* resets the timer to be disabled and unmasked and is compliant with
* the ARMv7 architecture.
*/
- vcpu_vtimer(vcpu)->cnt_ctl = 0;
- vcpu_ptimer(vcpu)->cnt_ctl = 0;
+ timer_set_ctl(vcpu_vtimer(vcpu), 0);
+ timer_set_ctl(vcpu_ptimer(vcpu), 0);

if (timer->enabled) {
kvm_timer_update_irq(vcpu, false, vcpu_vtimer(vcpu));
@@ -677,13 +764,13 @@ static void update_vtimer_cntvoff(struct kvm_vcpu *vcpu, u64 cntvoff)

mutex_lock(&kvm->lock);
kvm_for_each_vcpu(i, tmp, kvm)
- vcpu_vtimer(tmp)->cntvoff = cntvoff;
+ timer_set_offset(vcpu_vtimer(tmp), cntvoff);

/*
* When called from the vcpu create path, the CPU being created is not
* included in the loop above, so we just set it here as well.
*/
- vcpu_vtimer(vcpu)->cntvoff = cntvoff;
+ timer_set_offset(vcpu_vtimer(vcpu), cntvoff);
mutex_unlock(&kvm->lock);
}

@@ -693,9 +780,12 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);

+ vtimer->vcpu = vcpu;
+ ptimer->vcpu = vcpu;
+
/* Synchronize cntvoff across all vtimers of a VM. */
update_vtimer_cntvoff(vcpu, kvm_phys_timer_read());
- ptimer->cntvoff = 0;
+ timer_set_offset(ptimer, 0);

hrtimer_init(&timer->bg_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
timer->bg_timer.function = kvm_bg_timer_expire;
@@ -713,9 +803,6 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)

vtimer->host_timer_irq_flags = host_vtimer_irq_flags;
ptimer->host_timer_irq_flags = host_ptimer_irq_flags;
-
- vtimer->vcpu = vcpu;
- ptimer->vcpu = vcpu;
}

static void kvm_timer_init_interrupt(void *info)
@@ -765,10 +852,12 @@ static u64 read_timer_ctl(struct arch_timer_context *timer)
* UNKNOWN when ENABLE bit is 0, so we chose to set ISTATUS bit
* regardless of ENABLE bit for our implementation convenience.
*/
+ u32 ctl = timer_get_ctl(timer);
+
if (!kvm_timer_compute_delta(timer))
- return timer->cnt_ctl | ARCH_TIMER_CTRL_IT_STAT;
- else
- return timer->cnt_ctl;
+ ctl |= ARCH_TIMER_CTRL_IT_STAT;
+
+ return ctl;
}

u64 kvm_arm_timer_get_reg(struct kvm_vcpu *vcpu, u64 regid)
@@ -804,8 +893,8 @@ static u64 kvm_arm_timer_read(struct kvm_vcpu *vcpu,

switch (treg) {
case TIMER_REG_TVAL:
- val = timer->cnt_cval - kvm_phys_timer_read() + timer->cntvoff;
- val &= lower_32_bits(val);
+ val = timer_get_cval(timer) - kvm_phys_timer_read() + timer_get_offset(timer);
+ val = lower_32_bits(val);
break;

case TIMER_REG_CTL:
@@ -813,11 +902,11 @@ static u64 kvm_arm_timer_read(struct kvm_vcpu *vcpu,
break;

case TIMER_REG_CVAL:
- val = timer->cnt_cval;
+ val = timer_get_cval(timer);
break;

case TIMER_REG_CNT:
- val = kvm_phys_timer_read() - timer->cntvoff;
+ val = kvm_phys_timer_read() - timer_get_offset(timer);
break;

default:
@@ -851,15 +940,15 @@ static void kvm_arm_timer_write(struct kvm_vcpu *vcpu,
{
switch (treg) {
case TIMER_REG_TVAL:
- timer->cnt_cval = kvm_phys_timer_read() - timer->cntvoff + (s32)val;
+ timer_set_cval(timer, kvm_phys_timer_read() - timer_get_offset(timer) + (s32)val);
break;

case TIMER_REG_CTL:
- timer->cnt_ctl = val & ~ARCH_TIMER_CTRL_IT_STAT;
+ timer_set_ctl(timer, val & ~ARCH_TIMER_CTRL_IT_STAT);
break;

case TIMER_REG_CVAL:
- timer->cnt_cval = val;
+ timer_set_cval(timer, val);
break;

default:
diff --git a/virt/kvm/arm/trace.h b/virt/kvm/arm/trace.h
index cc94ccc688217..ff09cd493e480 100644
--- a/virt/kvm/arm/trace.h
+++ b/virt/kvm/arm/trace.h
@@ -302,8 +302,8 @@ TRACE_EVENT(kvm_timer_save_state,
),

TP_fast_assign(
- __entry->ctl = ctx->cnt_ctl;
- __entry->cval = ctx->cnt_cval;
+ __entry->ctl = timer_get_ctl(ctx);
+ __entry->cval = timer_get_cval(ctx);
__entry->timer_idx = arch_timer_ctx_index(ctx);
),

@@ -324,8 +324,8 @@ TRACE_EVENT(kvm_timer_restore_state,
),

TP_fast_assign(
- __entry->ctl = ctx->cnt_ctl;
- __entry->cval = ctx->cnt_cval;
+ __entry->ctl = timer_get_ctl(ctx);
+ __entry->cval = timer_get_cval(ctx);
__entry->timer_idx = arch_timer_ctx_index(ctx);
),

--
2.26.1