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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

arch/arm/include/asm/kvm_asm.h

+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

arch/arm/kernel/asm-offsets.c

+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));

arch/arm/kvm/arm.c

+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);

arch/arm/kvm/coproc.c

+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 */

arch/arm/kvm/interrupts_head.S

+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