[v2,49/94] KVM: arm64: nv: Propagate CNTVOFF_EL2 to the virtual EL1 timer

Commit Message

Marc Zyngier Feb. 11, 2020, 5:48 p.m. UTC

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 <[e-mail]>
---
 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(-)

Patch

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();
 	}