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Commit c7e3ba64 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

ARM: KVM: arch_timers: Add timer world switch



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: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarChristoffer Dall <c.dall@virtualopensystems.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 53e72406
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+2 −1
Original line number Diff line number Diff line
@@ -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
+6 −0
Original line number Diff line number Diff line
@@ -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));
+3 −0
Original line number Diff line number Diff line
@@ -718,6 +718,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
			vcpu_pause(vcpu);

		kvm_vgic_flush_hwstate(vcpu);
		kvm_timer_flush_hwstate(vcpu);

		local_irq_disable();

@@ -731,6 +732,7 @@ 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;
		}
@@ -764,6 +766,7 @@ 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);
+4 −0
Original line number Diff line number Diff line
@@ -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 */
+59 −0
Original line number Diff line number Diff line
@@ -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

/*
@@ -310,6 +318,14 @@ vcpu .req r0 @ vcpu pointer always in r0
 * Assumes vcpu pointer in vcpu reg
 */
.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
@@ -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