aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorJintack Lim <jintack@cs.columbia.edu>2017-02-03 10:20:08 -0500
committerMarc Zyngier <marc.zyngier@arm.com>2017-02-08 15:13:37 +0000
commit7b6b46311a8562fb3a9e035ed6ffab6d49c28886 (patch)
tree172797dd826ae77d749907bc1bd30cf2687f9509
parentKVM: arm64: Add the EL1 physical timer access handler (diff)
downloadlinux-dev-7b6b46311a8562fb3a9e035ed6ffab6d49c28886.tar.xz
linux-dev-7b6b46311a8562fb3a9e035ed6ffab6d49c28886.zip
KVM: arm/arm64: Emulate the EL1 phys timer registers
Emulate read and write operations to CNTP_TVAL, CNTP_CVAL and CNTP_CTL. Now VMs are able to use the EL1 physical timer. Signed-off-by: Jintack Lim <jintack@cs.columbia.edu> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
-rw-r--r--arch/arm64/kvm/sys_regs.c37
-rw-r--r--include/kvm/arm_arch_timer.h2
-rw-r--r--virt/kvm/arm/arch_timer.c2
3 files changed, 37 insertions, 4 deletions
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 1cd3464ff88d..0e26f8c2b56f 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -824,7 +824,14 @@ static bool access_cntp_tval(struct kvm_vcpu *vcpu,
struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
- kvm_inject_undefined(vcpu);
+ struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
+ u64 now = kvm_phys_timer_read();
+
+ if (p->is_write)
+ ptimer->cnt_cval = p->regval + now;
+ else
+ p->regval = ptimer->cnt_cval - now;
+
return true;
}
@@ -832,7 +839,25 @@ static bool access_cntp_ctl(struct kvm_vcpu *vcpu,
struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
- kvm_inject_undefined(vcpu);
+ struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
+
+ if (p->is_write) {
+ /* ISTATUS bit is read-only */
+ ptimer->cnt_ctl = p->regval & ~ARCH_TIMER_CTRL_IT_STAT;
+ } else {
+ u64 now = kvm_phys_timer_read();
+
+ p->regval = ptimer->cnt_ctl;
+ /*
+ * Set ISTATUS bit if it's expired.
+ * Note that according to ARMv8 ARM Issue A.k, ISTATUS bit is
+ * UNKNOWN when ENABLE bit is 0, so we chose to set ISTATUS bit
+ * regardless of ENABLE bit for our implementation convenience.
+ */
+ if (ptimer->cnt_cval <= now)
+ p->regval |= ARCH_TIMER_CTRL_IT_STAT;
+ }
+
return true;
}
@@ -840,7 +865,13 @@ static bool access_cntp_cval(struct kvm_vcpu *vcpu,
struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
- kvm_inject_undefined(vcpu);
+ struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
+
+ if (p->is_write)
+ ptimer->cnt_cval = p->regval;
+ else
+ p->regval = ptimer->cnt_cval;
+
return true;
}
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index f1d2fba0b9c6..fe797d6ef89d 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -72,6 +72,8 @@ bool kvm_timer_should_fire(struct arch_timer_context *timer_ctx);
void kvm_timer_schedule(struct kvm_vcpu *vcpu);
void kvm_timer_unschedule(struct kvm_vcpu *vcpu);
+u64 kvm_phys_timer_read(void);
+
void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu);
void kvm_timer_init_vhe(void);
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 33257b560f74..35d7100e0815 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -40,7 +40,7 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu)
vcpu_vtimer(vcpu)->active_cleared_last = false;
}
-static u64 kvm_phys_timer_read(void)
+u64 kvm_phys_timer_read(void)
{
return timecounter->cc->read(timecounter->cc);
}