Hi Marc,
On Thu, Mar 30, 2023 at 06:47:44PM +0100, Marc Zyngier wrote:
> With ECV and CNTPOFF_EL2, it is very easy to offer an offset for
> the physical timer. So let's do just that.
>
> Nothing can set the offset yet, so this should have no effect
> whatsoever (famous last words...).
>
> Reviewed-by: Colton Lewis <coltonlewis@xxxxxxxxxx>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
> arch/arm64/kvm/arch_timer.c | 18 +++++++++++++++++-
> arch/arm64/kvm/hypercalls.c | 2 +-
> include/clocksource/arm_arch_timer.h | 1 +
> include/kvm/arm_arch_timer.h | 2 ++
> 4 files changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
> index 9515c645f03d..3118ea0a1b41 100644
> --- a/arch/arm64/kvm/arch_timer.c
> +++ b/arch/arm64/kvm/arch_timer.c
> @@ -52,6 +52,11 @@ static u64 kvm_arm_timer_read(struct kvm_vcpu *vcpu,
> struct arch_timer_context *timer,
> enum kvm_arch_timer_regs treg);
>
> +static bool has_cntpoff(void)
> +{
> + return (has_vhe() && cpus_have_final_cap(ARM64_HAS_ECV_CNTPOFF));
> +}
> +
> u32 timer_get_ctl(struct arch_timer_context *ctxt)
> {
> struct kvm_vcpu *vcpu = ctxt->vcpu;
> @@ -84,7 +89,7 @@ u64 timer_get_cval(struct arch_timer_context *ctxt)
>
> static u64 timer_get_offset(struct arch_timer_context *ctxt)
> {
> - if (ctxt->offset.vm_offset)
> + if (ctxt && ctxt->offset.vm_offset)
> return *ctxt->offset.vm_offset;
Reviewed-by: Reiji Watanabe <reijiw@xxxxxxxxxx>
Nit: This particular change appears to be unnecessary in this patch.
(needed in the following patches ?)
Thank you,
Reiji
>
> return 0;
> @@ -432,6 +437,12 @@ static void set_cntvoff(u64 cntvoff)
> kvm_call_hyp(__kvm_timer_set_cntvoff, cntvoff);
> }
>
> +static void set_cntpoff(u64 cntpoff)
> +{
> + if (has_cntpoff())
> + write_sysreg_s(cntpoff, SYS_CNTPOFF_EL2);
> +}
> +
> static void timer_save_state(struct arch_timer_context *ctx)
> {
> struct arch_timer_cpu *timer = vcpu_timer(ctx->vcpu);
> @@ -480,6 +491,7 @@ static void timer_save_state(struct arch_timer_context *ctx)
> write_sysreg_el0(0, SYS_CNTP_CTL);
> isb();
>
> + set_cntpoff(0);
> break;
> case NR_KVM_TIMERS:
> BUG();
> @@ -550,6 +562,7 @@ static void timer_restore_state(struct arch_timer_context *ctx)
> write_sysreg_el0(timer_get_ctl(ctx), SYS_CNTV_CTL);
> break;
> case TIMER_PTIMER:
> + set_cntpoff(timer_get_offset(ctx));
> write_sysreg_el0(timer_get_cval(ctx), SYS_CNTP_CVAL);
> isb();
> write_sysreg_el0(timer_get_ctl(ctx), SYS_CNTP_CTL);
> @@ -767,6 +780,7 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
> vtimer->vcpu = vcpu;
> vtimer->offset.vm_offset = &vcpu->kvm->arch.timer_data.voffset;
> ptimer->vcpu = vcpu;
> + ptimer->offset.vm_offset = &vcpu->kvm->arch.timer_data.poffset;
>
> /* Synchronize cntvoff across all vtimers of a VM. */
> timer_set_offset(vtimer, kvm_phys_timer_read());
> @@ -1297,6 +1311,8 @@ void kvm_timer_init_vhe(void)
> val = read_sysreg(cnthctl_el2);
> val |= (CNTHCTL_EL1PCEN << cnthctl_shift);
> val |= (CNTHCTL_EL1PCTEN << cnthctl_shift);
> + if (cpus_have_final_cap(ARM64_HAS_ECV_CNTPOFF))
> + val |= CNTHCTL_ECV;
> write_sysreg(val, cnthctl_el2);
> }
>
> diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
> index 5da884e11337..39a4707e081d 100644
> --- a/arch/arm64/kvm/hypercalls.c
> +++ b/arch/arm64/kvm/hypercalls.c
> @@ -47,7 +47,7 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val)
> cycles = systime_snapshot.cycles - vcpu->kvm->arch.timer_data.voffset;
> break;
> case KVM_PTP_PHYS_COUNTER:
> - cycles = systime_snapshot.cycles;
> + cycles = systime_snapshot.cycles - vcpu->kvm->arch.timer_data.poffset;
> break;
> default:
> return;
> diff --git a/include/clocksource/arm_arch_timer.h b/include/clocksource/arm_arch_timer.h
> index 057c8964aefb..cbbc9a6dc571 100644
> --- a/include/clocksource/arm_arch_timer.h
> +++ b/include/clocksource/arm_arch_timer.h
> @@ -21,6 +21,7 @@
> #define CNTHCTL_EVNTEN (1 << 2)
> #define CNTHCTL_EVNTDIR (1 << 3)
> #define CNTHCTL_EVNTI (0xF << 4)
> +#define CNTHCTL_ECV (1 << 12)
>
> enum arch_timer_reg {
> ARCH_TIMER_REG_CTRL,
> diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
> index 70d47c4adc6a..2dd0fd2406fb 100644
> --- a/include/kvm/arm_arch_timer.h
> +++ b/include/kvm/arm_arch_timer.h
> @@ -34,6 +34,8 @@ struct arch_timer_offset {
> struct arch_timer_vm_data {
> /* Offset applied to the virtual timer/counter */
> u64 voffset;
> + /* Offset applied to the physical timer/counter */
> + u64 poffset;
> };
>
> struct arch_timer_context {
> --
> 2.34.1
>
