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Commit 1c810636 authored by Alexander Graf's avatar Alexander Graf
Browse files

KVM: PPC: BookE: Implement EPR exit 



The External Proxy Facility in FSL BookE chips allows the interrupt
controller to automatically acknowledge an interrupt as soon as a
core gets its pending external interrupt delivered.

Today, user space implements the interrupt controller, so we need to
check on it during such a cycle.

This patch implements logic for user space to enable EPR exiting,
disable EPR exiting and EPR exiting itself, so that user space can
acknowledge an interrupt when an external interrupt has successfully
been delivered into the guest vcpu.

Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
parent 37ecb257

Documentation/virtual/kvm/api.txt

+38 −2
Original line number Diff line number Diff line
@@ -2246,8 +2246,8 @@ executed a memory-mapped I/O instruction which could not be satisfied 
by kvm.  The 'data' member contains the written data if 'is_write' is

true, and should be filled by application code otherwise.



NOTE: For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_DCR

      and KVM_EXIT_PAPR the corresponding

NOTE: For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_DCR,

      KVM_EXIT_PAPR and KVM_EXIT_EPR the corresponding

operations are complete (and guest state is consistent) only after userspace

has re-entered the kernel with KVM_RUN.  The kernel side will first finish

incomplete operations and then check for pending signals.  Userspace
@@ -2366,6 +2366,25 @@ interrupt for the target subchannel has been dequeued and subchannel_id, 
subchannel_nr, io_int_parm and io_int_word contain the parameters for that

interrupt. ipb is needed for instruction parameter decoding.



		/* KVM_EXIT_EPR */

		struct {

			__u32 epr;

		} epr;



On FSL BookE PowerPC chips, the interrupt controller has a fast patch

interrupt acknowledge path to the core. When the core successfully

delivers an interrupt, it automatically populates the EPR register with

the interrupt vector number and acknowledges the interrupt inside

the interrupt controller.



In case the interrupt controller lives in user space, we need to do

the interrupt acknowledge cycle through it to fetch the next to be

delivered interrupt vector using this exit.



It gets triggered whenever both KVM_CAP_PPC_EPR are enabled and an

external interrupt has just been delivered into the guest. User space

should put the acknowledged interrupt vector into the 'epr' field.



		/* Fix the size of the union. */

		char padding[256];

	};
@@ -2501,3 +2520,20 @@ handled in-kernel, while the other I/O instructions are passed to userspace. 


When this capability is enabled, KVM_EXIT_S390_TSCH will occur on TEST

SUBCHANNEL intercepts.



6.5 KVM_CAP_PPC_EPR



Architectures: ppc

Parameters: args[0] defines whether the proxy facility is active

Returns: 0 on success; -1 on error



This capability enables or disables the delivery of interrupts through the

external proxy facility.



When enabled (args[0] != 0), every time the guest gets an external interrupt

delivered, it automatically exits into user space with a KVM_EXIT_EPR exit

to receive the topmost interrupt vector.



When disabled (args[0] == 0), behavior is as if this facility is unsupported.



When this capability is enabled, KVM_EXIT_EPR can occur.

arch/powerpc/include/asm/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -520,6 +520,8 @@ struct kvm_vcpu_arch { 
	u8 sane;

	u8 cpu_type;

	u8 hcall_needed;

	u8 epr_enabled;

	u8 epr_needed;



	u32 cpr0_cfgaddr; /* holds the last set cpr0_cfgaddr */

arch/powerpc/include/asm/kvm_ppc.h

+9 −0
Original line number Diff line number Diff line
@@ -264,6 +264,15 @@ static inline void kvm_linear_init(void) 
{}

#endif



static inline void kvmppc_set_epr(struct kvm_vcpu *vcpu, u32 epr)

{

#ifdef CONFIG_KVM_BOOKE_HV

	mtspr(SPRN_GEPR, epr);

#elif defined(CONFIG_BOOKE)

	vcpu->arch.epr = epr;

#endif

}



int kvm_vcpu_ioctl_config_tlb(struct kvm_vcpu *vcpu,

			      struct kvm_config_tlb *cfg);

int kvm_vcpu_ioctl_dirty_tlb(struct kvm_vcpu *vcpu,

arch/powerpc/kvm/booke.c

+13 −1
Original line number Diff line number Diff line
@@ -306,7 +306,7 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu, 
{

	int allowed = 0;

	ulong msr_mask = 0;

	bool update_esr = false, update_dear = false;

	bool update_esr = false, update_dear = false, update_epr = false;

	ulong crit_raw = vcpu->arch.shared->critical;

	ulong crit_r1 = kvmppc_get_gpr(vcpu, 1);

	bool crit;
@@ -330,6 +330,9 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu, 
		keep_irq = true;

	}



	if ((priority == BOOKE_IRQPRIO_EXTERNAL) && vcpu->arch.epr_enabled)

		update_epr = true;



	switch (priority) {

	case BOOKE_IRQPRIO_DTLB_MISS:

	case BOOKE_IRQPRIO_DATA_STORAGE:
@@ -408,6 +411,8 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu, 
			set_guest_esr(vcpu, vcpu->arch.queued_esr);

		if (update_dear == true)

			set_guest_dear(vcpu, vcpu->arch.queued_dear);

		if (update_epr == true)

			kvm_make_request(KVM_REQ_EPR_EXIT, vcpu);



		new_msr &= msr_mask;

#if defined(CONFIG_64BIT)
@@ -615,6 +620,13 @@ int kvmppc_core_check_requests(struct kvm_vcpu *vcpu) 
		r = 0;

	}



	if (kvm_check_request(KVM_REQ_EPR_EXIT, vcpu)) {

		vcpu->run->epr.epr = 0;

		vcpu->arch.epr_needed = true;

		vcpu->run->exit_reason = KVM_EXIT_EPR;

		r = 0;

	}



	return r;

}

arch/powerpc/kvm/powerpc.c

+10 −0
Original line number Diff line number Diff line
@@ -306,6 +306,7 @@ int kvm_dev_ioctl_check_extension(long ext) 
#ifdef CONFIG_BOOKE

	case KVM_CAP_PPC_BOOKE_SREGS:

	case KVM_CAP_PPC_BOOKE_WATCHDOG:

	case KVM_CAP_PPC_EPR:

#else

	case KVM_CAP_PPC_SEGSTATE:

	case KVM_CAP_PPC_HIOR:
@@ -721,6 +722,11 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) 
		for (i = 0; i < 9; ++i)

			kvmppc_set_gpr(vcpu, 4 + i, run->papr_hcall.args[i]);

		vcpu->arch.hcall_needed = 0;

#ifdef CONFIG_BOOKE

	} else if (vcpu->arch.epr_needed) {

		kvmppc_set_epr(vcpu, run->epr.epr);

		vcpu->arch.epr_needed = 0;

#endif

	}



	r = kvmppc_vcpu_run(run, vcpu);
@@ -762,6 +768,10 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu, 
		r = 0;

		vcpu->arch.papr_enabled = true;

		break;

	case KVM_CAP_PPC_EPR:

		r = 0;

		vcpu->arch.epr_enabled = cap->args[0];

		break;

#ifdef CONFIG_BOOKE

	case KVM_CAP_PPC_BOOKE_WATCHDOG:

		r = 0;