Commit c57875f5 authored by Suresh Warrier's avatar Suresh Warrier Committed by Paul Mackerras
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KVM: PPC: Book3S HV: Enable IRQ bypass 



Add the irq_bypass_add_producer and irq_bypass_del_producer
functions. These functions get called whenever a GSI is being
defined for a guest. They create/remove the mapping between
host real IRQ numbers and the guest GSI.

Add the following helper functions to manage the
passthrough IRQ map.

kvmppc_set_passthru_irq()
  Creates a mapping in the passthrough IRQ map that maps a host
  IRQ to a guest GSI. It allocates the structure (one per guest VM)
  the first time it is called.

kvmppc_clr_passthru_irq()
  Removes the passthrough IRQ map entry given a guest GSI.
  The passthrough IRQ map structure is not freed even when the
  number of mapped entries goes to zero. It is only freed when
  the VM is destroyed.

[paulus@ozlabs.org - modified to use is_pnv_opal_msi() rather than
 requiring all passed-through interrupts to use the same irq_chip;
 changed deletion so it zeroes out the r_hwirq field rather than
 copying the last entry down and decrementing the number of entries.]

Signed-off-by: default avatarSuresh Warrier <warrier@linux.vnet.ibm.com>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
parent 8daaafc8

arch/powerpc/kvm/book3s_hv.c

+159 −1
Original line number Diff line number Diff line
@@ -53,10 +53,13 @@ 
#include <asm/smp.h>

#include <asm/dbell.h>

#include <asm/hmi.h>

#include <asm/pnv-pci.h>

#include <linux/gfp.h>

#include <linux/vmalloc.h>

#include <linux/highmem.h>

#include <linux/hugetlb.h>

#include <linux/kvm_irqfd.h>

#include <linux/irqbypass.h>

#include <linux/module.h>

#include <linux/compiler.h>
@@ -3377,6 +3380,8 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm) 
	kvmppc_free_vcores(kvm);



	kvmppc_free_hpt(kvm);



	kvmppc_free_pimap(kvm);

}



/* We don't need to emulate any privileged instructions or dcbz */
@@ -3419,10 +3424,159 @@ void kvmppc_free_pimap(struct kvm *kvm) 
	kfree(kvm->arch.pimap);

}



struct kvmppc_passthru_irqmap *kvmppc_alloc_pimap(void)

static struct kvmppc_passthru_irqmap *kvmppc_alloc_pimap(void)

{

	return kzalloc(sizeof(struct kvmppc_passthru_irqmap), GFP_KERNEL);

}



static int kvmppc_set_passthru_irq(struct kvm *kvm, int host_irq, int guest_gsi)

{

	struct irq_desc *desc;

	struct kvmppc_irq_map *irq_map;

	struct kvmppc_passthru_irqmap *pimap;

	struct irq_chip *chip;

	int i;



	desc = irq_to_desc(host_irq);

	if (!desc)

		return -EIO;



	mutex_lock(&kvm->lock);



	pimap = kvm->arch.pimap;

	if (pimap == NULL) {

		/* First call, allocate structure to hold IRQ map */

		pimap = kvmppc_alloc_pimap();

		if (pimap == NULL) {

			mutex_unlock(&kvm->lock);

			return -ENOMEM;

		}

		kvm->arch.pimap = pimap;

	}



	/*

	 * For now, we only support interrupts for which the EOI operation

	 * is an OPAL call followed by a write to XIRR, since that's

	 * what our real-mode EOI code does.

	 */

	chip = irq_data_get_irq_chip(&desc->irq_data);

	if (!chip || !is_pnv_opal_msi(chip)) {

		pr_warn("kvmppc_set_passthru_irq_hv: Could not assign IRQ map for (%d,%d)\n",

			host_irq, guest_gsi);

		mutex_unlock(&kvm->lock);

		return -ENOENT;

	}



	/*

	 * See if we already have an entry for this guest IRQ number.

	 * If it's mapped to a hardware IRQ number, that's an error,

	 * otherwise re-use this entry.

	 */

	for (i = 0; i < pimap->n_mapped; i++) {

		if (guest_gsi == pimap->mapped[i].v_hwirq) {

			if (pimap->mapped[i].r_hwirq) {

				mutex_unlock(&kvm->lock);

				return -EINVAL;

			}

			break;

		}

	}



	if (i == KVMPPC_PIRQ_MAPPED) {

		mutex_unlock(&kvm->lock);

		return -EAGAIN;		/* table is full */

	}



	irq_map = &pimap->mapped[i];



	irq_map->v_hwirq = guest_gsi;

	irq_map->r_hwirq = desc->irq_data.hwirq;

	irq_map->desc = desc;



	if (i == pimap->n_mapped)

		pimap->n_mapped++;



	mutex_unlock(&kvm->lock);



	return 0;

}



static int kvmppc_clr_passthru_irq(struct kvm *kvm, int host_irq, int guest_gsi)

{

	struct irq_desc *desc;

	struct kvmppc_passthru_irqmap *pimap;

	int i;



	desc = irq_to_desc(host_irq);

	if (!desc)

		return -EIO;



	mutex_lock(&kvm->lock);



	if (kvm->arch.pimap == NULL) {

		mutex_unlock(&kvm->lock);

		return 0;

	}

	pimap = kvm->arch.pimap;



	for (i = 0; i < pimap->n_mapped; i++) {

		if (guest_gsi == pimap->mapped[i].v_hwirq)

			break;

	}



	if (i == pimap->n_mapped) {

		mutex_unlock(&kvm->lock);

		return -ENODEV;

	}



	/* invalidate the entry */

	pimap->mapped[i].r_hwirq = 0;



	/*

	 * We don't free this structure even when the count goes to

	 * zero. The structure is freed when we destroy the VM.

	 */



	mutex_unlock(&kvm->lock);

	return 0;

}



static int kvmppc_irq_bypass_add_producer_hv(struct irq_bypass_consumer *cons,

					     struct irq_bypass_producer *prod)

{

	int ret = 0;

	struct kvm_kernel_irqfd *irqfd =

		container_of(cons, struct kvm_kernel_irqfd, consumer);



	irqfd->producer = prod;



	ret = kvmppc_set_passthru_irq(irqfd->kvm, prod->irq, irqfd->gsi);

	if (ret)

		pr_info("kvmppc_set_passthru_irq (irq %d, gsi %d) fails: %d\n",

			prod->irq, irqfd->gsi, ret);



	return ret;

}



static void kvmppc_irq_bypass_del_producer_hv(struct irq_bypass_consumer *cons,

					      struct irq_bypass_producer *prod)

{

	int ret;

	struct kvm_kernel_irqfd *irqfd =

		container_of(cons, struct kvm_kernel_irqfd, consumer);



	irqfd->producer = NULL;



	/*

	 * When producer of consumer is unregistered, we change back to

	 * default external interrupt handling mode - KVM real mode

	 * will switch back to host.

	 */

	ret = kvmppc_clr_passthru_irq(irqfd->kvm, prod->irq, irqfd->gsi);

	if (ret)

		pr_warn("kvmppc_clr_passthru_irq (irq %d, gsi %d) fails: %d\n",

			prod->irq, irqfd->gsi, ret);

}

#endif



static long kvm_arch_vm_ioctl_hv(struct file *filp,
@@ -3543,6 +3697,10 @@ static struct kvmppc_ops kvm_ops_hv = { 
	.fast_vcpu_kick = kvmppc_fast_vcpu_kick_hv,

	.arch_vm_ioctl  = kvm_arch_vm_ioctl_hv,

	.hcall_implemented = kvmppc_hcall_impl_hv,

#ifdef CONFIG_KVM_XICS

	.irq_bypass_add_producer = kvmppc_irq_bypass_add_producer_hv,

	.irq_bypass_del_producer = kvmppc_irq_bypass_del_producer_hv,

#endif

};



static int kvm_init_subcore_bitmap(void)

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