ARM: KVM: arch_timers: Add guest timer core support
Add some the architected timer related infrastructure, and support timer
interrupt injection, which can happen as a resultof three possible
events:
- The virtual timer interrupt has fired while we were still
executing the guest
- The timer interrupt hasn't fired, but it expired while we
were doing the world switch
- A hrtimer we programmed earlier has fired
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S
index 8c875d5..06f2513 100644
--- a/arch/arm/kvm/interrupts_head.S
+++ b/arch/arm/kvm/interrupts_head.S
@@ -453,6 +453,37 @@
#endif
.endm
+#define CNTHCTL_PL1PCTEN (1 << 0)
+#define CNTHCTL_PL1PCEN (1 << 1)
+
+/*
+ * Save the timer state onto the VCPU and allow physical timer/counter access
+ * for the host.
+ *
+ * Assumes vcpu pointer in vcpu reg
+ */
+.macro save_timer_state
+ @ Allow physical timer/counter access for the host
+ mrc p15, 4, r2, c14, c1, 0 @ CNTHCTL
+ orr r2, r2, #(CNTHCTL_PL1PCEN | CNTHCTL_PL1PCTEN)
+ mcr p15, 4, r2, c14, c1, 0 @ CNTHCTL
+.endm
+
+/*
+ * Load the timer state from the VCPU and deny physical timer/counter access
+ * for the host.
+ *
+ * Assumes vcpu pointer in vcpu reg
+ */
+.macro restore_timer_state
+ @ Disallow physical timer access for the guest
+ @ Physical counter access is allowed
+ mrc p15, 4, r2, c14, c1, 0 @ CNTHCTL
+ orr r2, r2, #CNTHCTL_PL1PCTEN
+ bic r2, r2, #CNTHCTL_PL1PCEN
+ mcr p15, 4, r2, c14, c1, 0 @ CNTHCTL
+.endm
+
.equ vmentry, 0
.equ vmexit, 1