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Commit 2d34d1c3 authored by Suraj Jitindar Singh's avatar Suraj Jitindar Singh Committed by Paul Mackerras
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KVM: PPC: Book3S HV: Implement virtual mode H_PAGE_INIT handler 



Implement a virtual mode handler for the H_CALL H_PAGE_INIT which can be
used to zero or copy a guest page. The page is defined to be 4k and must
be 4k aligned.

The in-kernel handler halves the time to handle this H_CALL compared to
handling it in userspace for a radix guest.

Signed-off-by: default avatarSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
parent 345077c8

arch/powerpc/kvm/book3s_hv.c

+80 −0
Original line number Diff line number Diff line
@@ -801,6 +801,80 @@ static int kvmppc_h_set_mode(struct kvm_vcpu *vcpu, unsigned long mflags, 
	}

}



/* Copy guest memory in place - must reside within a single memslot */

static int kvmppc_copy_guest(struct kvm *kvm, gpa_t to, gpa_t from,

				  unsigned long len)

{

	struct kvm_memory_slot *to_memslot = NULL;

	struct kvm_memory_slot *from_memslot = NULL;

	unsigned long to_addr, from_addr;

	int r;



	/* Get HPA for from address */

	from_memslot = gfn_to_memslot(kvm, from >> PAGE_SHIFT);

	if (!from_memslot)

		return -EFAULT;

	if ((from + len) >= ((from_memslot->base_gfn + from_memslot->npages)

			     << PAGE_SHIFT))

		return -EINVAL;

	from_addr = gfn_to_hva_memslot(from_memslot, from >> PAGE_SHIFT);

	if (kvm_is_error_hva(from_addr))

		return -EFAULT;

	from_addr |= (from & (PAGE_SIZE - 1));



	/* Get HPA for to address */

	to_memslot = gfn_to_memslot(kvm, to >> PAGE_SHIFT);

	if (!to_memslot)

		return -EFAULT;

	if ((to + len) >= ((to_memslot->base_gfn + to_memslot->npages)

			   << PAGE_SHIFT))

		return -EINVAL;

	to_addr = gfn_to_hva_memslot(to_memslot, to >> PAGE_SHIFT);

	if (kvm_is_error_hva(to_addr))

		return -EFAULT;

	to_addr |= (to & (PAGE_SIZE - 1));



	/* Perform copy */

	r = raw_copy_in_user((void __user *)to_addr, (void __user *)from_addr,

			     len);

	if (r)

		return -EFAULT;

	mark_page_dirty(kvm, to >> PAGE_SHIFT);

	return 0;

}



static long kvmppc_h_page_init(struct kvm_vcpu *vcpu, unsigned long flags,

			       unsigned long dest, unsigned long src)

{

	u64 pg_sz = SZ_4K;		/* 4K page size */

	u64 pg_mask = SZ_4K - 1;

	int ret;



	/* Check for invalid flags (H_PAGE_SET_LOANED covers all CMO flags) */

	if (flags & ~(H_ICACHE_INVALIDATE | H_ICACHE_SYNCHRONIZE |

		      H_ZERO_PAGE | H_COPY_PAGE | H_PAGE_SET_LOANED))

		return H_PARAMETER;



	/* dest (and src if copy_page flag set) must be page aligned */

	if ((dest & pg_mask) || ((flags & H_COPY_PAGE) && (src & pg_mask)))

		return H_PARAMETER;



	/* zero and/or copy the page as determined by the flags */

	if (flags & H_COPY_PAGE) {

		ret = kvmppc_copy_guest(vcpu->kvm, dest, src, pg_sz);

		if (ret < 0)

			return H_PARAMETER;

	} else if (flags & H_ZERO_PAGE) {

		ret = kvm_clear_guest(vcpu->kvm, dest, pg_sz);

		if (ret < 0)

			return H_PARAMETER;

	}



	/* We can ignore the remaining flags */



	return H_SUCCESS;

}



static int kvm_arch_vcpu_yield_to(struct kvm_vcpu *target)

{

	struct kvmppc_vcore *vcore = target->arch.vcore;
@@ -1003,6 +1077,11 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu) 
		if (nesting_enabled(vcpu->kvm))

			ret = kvmhv_copy_tofrom_guest_nested(vcpu);

		break;

	case H_PAGE_INIT:

		ret = kvmppc_h_page_init(vcpu, kvmppc_get_gpr(vcpu, 4),

					 kvmppc_get_gpr(vcpu, 5),

					 kvmppc_get_gpr(vcpu, 6));

		break;

	default:

		return RESUME_HOST;

	}
@@ -1047,6 +1126,7 @@ static int kvmppc_hcall_impl_hv(unsigned long cmd) 
	case H_IPOLL:

	case H_XIRR_X:

#endif

	case H_PAGE_INIT:

		return 1;

	}