We need to allow a guest hypervisor to virtualize the virtual timer.
FOr that, let's propagate CNTVOFF_EL2 to the guest's view of that
timer.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 1 -
arch/arm64/kvm/sys_regs.c | 7 ++++++-
include/kvm/arm_arch_timer.h | 1 +
virt/kvm/arm/arch_timer.c | 8 ++++++++
4 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 36bb463dc16a..e35165de51a2 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -247,7 +247,6 @@ enum vcpu_sysreg {
RMR_EL2, /* Reset Management Register */
CONTEXTIDR_EL2, /* Context ID Register (EL2) */
TPIDR_EL2, /* EL2 Software Thread ID Register */
- CNTVOFF_EL2, /* Counter-timer Virtual Offset register */
CNTHCTL_EL2, /* Counter-timer Hypervisor Control register */
SP_EL2, /* EL2 Stack Pointer */
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 5d9ca3988745..7e2553480721 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1373,6 +1373,11 @@ static bool access_arch_timer(struct kvm_vcpu *vcpu,
tmr = TIMER_PTIMER;
treg = TIMER_REG_CVAL;
break;
+ case SYS_CNTVOFF_EL2:
+ tmr = TIMER_VTIMER;
+ treg = TIMER_REG_VOFF;
+ break;
+
default:
BUG();
}
@@ -2075,7 +2080,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_CONTEXTIDR_EL2), access_rw, reset_val, CONTEXTIDR_EL2, 0 },
{ SYS_DESC(SYS_TPIDR_EL2), access_rw, reset_val, TPIDR_EL2, 0 },
- { SYS_DESC(SYS_CNTVOFF_EL2), access_rw, reset_val, CNTVOFF_EL2, 0 },
+ { SYS_DESC(SYS_CNTVOFF_EL2), access_arch_timer },
{ SYS_DESC(SYS_CNTHCTL_EL2), access_rw, reset_val, CNTHCTL_EL2, 0 },
{ SYS_DESC(SYS_CNTHP_TVAL_EL2), access_arch_timer },
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index 3a5d9255120e..3389606f3029 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -23,6 +23,7 @@ enum kvm_arch_timer_regs {
TIMER_REG_CVAL,
TIMER_REG_TVAL,
TIMER_REG_CTL,
+ TIMER_REG_VOFF,
};
struct arch_timer_context {
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index c7edefced838..3c88a4c0a296 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -917,6 +917,10 @@ static u64 kvm_arm_timer_read(struct kvm_vcpu *vcpu,
val = kvm_phys_timer_read() - timer->cntvoff;
break;
+ case TIMER_REG_VOFF:
+ val = timer->cntvoff;
+ break;
+
default:
BUG();
}
@@ -959,6 +963,10 @@ static void kvm_arm_timer_write(struct kvm_vcpu *vcpu,
timer->cnt_cval = val;
break;
+ case TIMER_REG_VOFF:
+ timer->cntvoff = val;
+ break;
+
default:
BUG();
}
--
2.20.1
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