[PATCH v6 3/4] ARM: KVM: arch_timers: Add timer world switch
Christoffer Dall
c.dall at virtualopensystems.com
Wed Jan 16 13:03:30 EST 2013
From: Marc Zyngier <marc.zyngier at arm.com>
Do the necessary save/restore dance for the timers in the world
switch code. In the process, allow the guest to read the physical
counter, which is useful for its own clock_event_device.
Reviewed-by: Will Deacon <will.deacon at arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
Signed-off-by: Christoffer Dall <c.dall at virtualopensystems.com>
---
arch/arm/include/asm/kvm_asm.h | 3 +-
arch/arm/kernel/asm-offsets.c | 6 ++++
arch/arm/kvm/arm.c | 3 ++
arch/arm/kvm/coproc.c | 4 +++
arch/arm/kvm/interrupts_head.S | 59 ++++++++++++++++++++++++++++++++++++++++
5 files changed, 74 insertions(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 58d787b..8a60ed8 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -45,7 +45,8 @@
#define c13_TID_URW 23 /* Thread ID, User R/W */
#define c13_TID_URO 24 /* Thread ID, User R/O */
#define c13_TID_PRIV 25 /* Thread ID, Privileged */
-#define NR_CP15_REGS 26 /* Number of regs (incl. invalid) */
+#define c14_CNTKCTL 26 /* Timer Control Register (PL1) */
+#define NR_CP15_REGS 27 /* Number of regs (incl. invalid) */
#define ARM_EXCEPTION_RESET 0
#define ARM_EXCEPTION_UNDEFINED 1
diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index 17cea2e..5ce738b 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -179,6 +179,12 @@ int main(void)
DEFINE(VGIC_CPU_APR, offsetof(struct vgic_cpu, vgic_apr));
DEFINE(VGIC_CPU_LR, offsetof(struct vgic_cpu, vgic_lr));
DEFINE(VGIC_CPU_NR_LR, offsetof(struct vgic_cpu, nr_lr));
+#ifdef CONFIG_KVM_ARM_TIMER
+ DEFINE(VCPU_TIMER_CNTV_CTL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_ctl));
+ DEFINE(VCPU_TIMER_CNTV_CVAL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_cval));
+ DEFINE(KVM_TIMER_CNTVOFF, offsetof(struct kvm, arch.timer.cntvoff));
+ DEFINE(KVM_TIMER_ENABLED, offsetof(struct kvm, arch.timer.enabled));
+#endif
DEFINE(KVM_VGIC_VCTRL, offsetof(struct kvm, arch.vgic.vctrl_base));
#endif
DEFINE(KVM_VTTBR, offsetof(struct kvm, arch.vttbr));
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 68cb2b550..1a98b5c 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -707,6 +707,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
update_vttbr(vcpu->kvm);
kvm_vgic_flush_hwstate(vcpu);
+ kvm_timer_flush_hwstate(vcpu);
local_irq_disable();
@@ -720,6 +721,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
if (ret <= 0 || need_new_vmid_gen(vcpu->kvm)) {
local_irq_enable();
+ kvm_timer_sync_hwstate(vcpu);
kvm_vgic_sync_hwstate(vcpu);
continue;
}
@@ -759,6 +761,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
* Back from guest
*************************************************************/
+ kvm_timer_sync_hwstate(vcpu);
kvm_vgic_sync_hwstate(vcpu);
ret = handle_exit(vcpu, run, ret);
diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c
index d782638..4ea9a98 100644
--- a/arch/arm/kvm/coproc.c
+++ b/arch/arm/kvm/coproc.c
@@ -222,6 +222,10 @@ static const struct coproc_reg cp15_regs[] = {
NULL, reset_unknown, c13_TID_URO },
{ CRn(13), CRm( 0), Op1( 0), Op2( 4), is32,
NULL, reset_unknown, c13_TID_PRIV },
+
+ /* CNTKCTL: swapped by interrupt.S. */
+ { CRn(14), CRm( 1), Op1( 0), Op2( 0), is32,
+ NULL, reset_val, c14_CNTKCTL, 0x00000000 },
};
/* Target specific emulation tables */
diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S
index dea987e..d2442f9 100644
--- a/arch/arm/kvm/interrupts_head.S
+++ b/arch/arm/kvm/interrupts_head.S
@@ -300,6 +300,14 @@ vcpu .req r0 @ vcpu pointer always in r0
str r11, [vcpu, #CP15_OFFSET(c6_IFAR)]
str r12, [vcpu, #CP15_OFFSET(c12_VBAR)]
.endif
+
+ mrc p15, 0, r2, c14, c1, 0 @ CNTKCTL
+
+ .if \store_to_vcpu == 0
+ push {r2}
+ .else
+ str r2, [vcpu, #CP15_OFFSET(c14_CNTKCTL)]
+ .endif
.endm
/*
@@ -311,6 +319,14 @@ vcpu .req r0 @ vcpu pointer always in r0
*/
.macro write_cp15_state read_from_vcpu
.if \read_from_vcpu == 0
+ pop {r2}
+ .else
+ ldr r2, [vcpu, #CP15_OFFSET(c14_CNTKCTL)]
+ .endif
+
+ mcr p15, 0, r2, c14, c1, 0 @ CNTKCTL
+
+ .if \read_from_vcpu == 0
pop {r2-r12}
.else
ldr r2, [vcpu, #CP15_OFFSET(c13_CID)]
@@ -461,8 +477,28 @@ vcpu .req r0 @ vcpu pointer always in r0
* for the host.
*
* Assumes vcpu pointer in vcpu reg
+ * Clobbers r2-r5
*/
.macro save_timer_state
+#ifdef CONFIG_KVM_ARM_TIMER
+ ldr r4, [vcpu, #VCPU_KVM]
+ ldr r2, [r4, #KVM_TIMER_ENABLED]
+ cmp r2, #0
+ beq 1f
+
+ mrc p15, 0, r2, c14, c3, 1 @ CNTV_CTL
+ str r2, [vcpu, #VCPU_TIMER_CNTV_CTL]
+ bic r2, #1 @ Clear ENABLE
+ mcr p15, 0, r2, c14, c3, 1 @ CNTV_CTL
+ isb
+
+ mrrc p15, 3, r2, r3, c14 @ CNTV_CVAL
+ ldr r4, =VCPU_TIMER_CNTV_CVAL
+ add r5, vcpu, r4
+ strd r2, r3, [r5]
+
+1:
+#endif
@ Allow physical timer/counter access for the host
mrc p15, 4, r2, c14, c1, 0 @ CNTHCTL
orr r2, r2, #(CNTHCTL_PL1PCEN | CNTHCTL_PL1PCTEN)
@@ -474,6 +510,7 @@ vcpu .req r0 @ vcpu pointer always in r0
* for the host.
*
* Assumes vcpu pointer in vcpu reg
+ * Clobbers r2-r5
*/
.macro restore_timer_state
@ Disallow physical timer access for the guest
@@ -482,6 +519,28 @@ vcpu .req r0 @ vcpu pointer always in r0
orr r2, r2, #CNTHCTL_PL1PCTEN
bic r2, r2, #CNTHCTL_PL1PCEN
mcr p15, 4, r2, c14, c1, 0 @ CNTHCTL
+
+#ifdef CONFIG_KVM_ARM_TIMER
+ ldr r4, [vcpu, #VCPU_KVM]
+ ldr r2, [r4, #KVM_TIMER_ENABLED]
+ cmp r2, #0
+ beq 1f
+
+ ldr r2, [r4, #KVM_TIMER_CNTVOFF]
+ ldr r3, [r4, #(KVM_TIMER_CNTVOFF + 4)]
+ mcrr p15, 4, r2, r3, c14 @ CNTVOFF
+
+ ldr r4, =VCPU_TIMER_CNTV_CVAL
+ add r5, vcpu, r4
+ ldrd r2, r3, [r5]
+ mcrr p15, 3, r2, r3, c14 @ CNTV_CVAL
+ isb
+
+ ldr r2, [vcpu, #VCPU_TIMER_CNTV_CTL]
+ and r2, r2, #3
+ mcr p15, 0, r2, c14, c3, 1 @ CNTV_CTL
+1:
+#endif
.endm
.equ vmentry, 0
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