KVM: PPC: Book3S: Make kvmppc_ld return a more accurate error indication (1b2e33b0) · Commits · 戴 / test

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:

Paul Mackerras <paulus@samba.org> Signed-off-by:

Alexander Graf <agraf@suse.de>

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;
		}

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