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Commit 1b2e33b0 authored by Paul Mackerras's avatar Paul Mackerras Committed by Alexander Graf
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KVM: PPC: Book3S: Make kvmppc_ld return a more accurate error indication 



At present, kvmppc_ld calls kvmppc_xlate, and if kvmppc_xlate returns
any error indication, it returns -ENOENT, which is taken to mean an
HPTE not found error.  However, the error could have been a segment
found (no SLB entry) or a permission error.  Similarly,
kvmppc_pte_to_hva currently does permission checking, but any error
from it is taken by kvmppc_ld to mean that the access is an emulated
MMIO access.  Also, kvmppc_ld does no execute permission checking.

This fixes these problems by (a) returning any error from kvmppc_xlate
directly, (b) moving the permission check from kvmppc_pte_to_hva
into kvmppc_ld, and (c) adding an execute permission check to kvmppc_ld.

This is similar to what was done for kvmppc_st() by commit 82ff911317c3
("KVM: PPC: Deflect page write faults properly in kvmppc_st").

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
parent ef1af2e2

arch/powerpc/kvm/book3s.c

+12 −13
Original line number Diff line number Diff line
@@ -413,17 +413,10 @@ static hva_t kvmppc_bad_hva(void) 
	return PAGE_OFFSET;

}



static hva_t kvmppc_pte_to_hva(struct kvm_vcpu *vcpu, struct kvmppc_pte *pte,

			       bool read)

static hva_t kvmppc_pte_to_hva(struct kvm_vcpu *vcpu, struct kvmppc_pte *pte)

{

	hva_t hpage;



	if (read && !pte->may_read)

		goto err;



	if (!read && !pte->may_write)

		goto err;



	hpage = gfn_to_hva(vcpu->kvm, pte->raddr >> PAGE_SHIFT);

	if (kvm_is_error_hva(hpage))

		goto err;
@@ -462,15 +455,23 @@ int kvmppc_ld(struct kvm_vcpu *vcpu, ulong *eaddr, int size, void *ptr, 
{

	struct kvmppc_pte pte;

	hva_t hva = *eaddr;

	int rc;



	vcpu->stat.ld++;



	if (kvmppc_xlate(vcpu, *eaddr, data, false, &pte))

		goto nopte;

	rc = kvmppc_xlate(vcpu, *eaddr, data, false, &pte);

	if (rc)

		return rc;



	*eaddr = pte.raddr;



	hva = kvmppc_pte_to_hva(vcpu, &pte, true);

	if (!pte.may_read)

		return -EPERM;



	if (!data && !pte.may_execute)

		return -ENOEXEC;



	hva = kvmppc_pte_to_hva(vcpu, &pte);

	if (kvm_is_error_hva(hva))

		goto mmio;
@@ -481,8 +482,6 @@ int kvmppc_ld(struct kvm_vcpu *vcpu, ulong *eaddr, int size, void *ptr, 


	return EMULATE_DONE;



nopte:

	return -ENOENT;

mmio:

	return EMULATE_DO_MMIO;

}