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Commit 5cd92a95 authored by Paul Mackerras's avatar Paul Mackerras Committed by Alexander Graf
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KVM: PPC: Book3S PR: Correct errors in H_ENTER implementation 



The implementation of H_ENTER in PR KVM has some errors:

* With H_EXACT not set, if the HPTEG is full, we return H_PTEG_FULL
  as the return value of kvmppc_h_pr_enter, but the caller is expecting
  one of the EMULATE_* values.  The H_PTEG_FULL needs to go in the
  guest's R3 instead.

* With H_EXACT set, if the selected HPTE is already valid, the H_ENTER
  call should return a H_PTEG_FULL error.

This fixes these errors and also makes it write only the selected HPTE,
not the whole group, since only the selected HPTE has been modified.
This also micro-optimizes the calculations involving pte_index and i.

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
parent 03a9c903

arch/powerpc/kvm/book3s_pr_papr.c

+14 −5
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 
#include <asm/kvm_ppc.h>

#include <asm/kvm_book3s.h>



#define HPTE_SIZE	16		/* bytes per HPT entry */



static unsigned long get_pteg_addr(struct kvm_vcpu *vcpu, long pte_index)

{

	struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
@@ -40,32 +42,39 @@ static int kvmppc_h_pr_enter(struct kvm_vcpu *vcpu) 
	long pte_index = kvmppc_get_gpr(vcpu, 5);

	unsigned long pteg[2 * 8];

	unsigned long pteg_addr, i, *hpte;

	long int ret;



	i = pte_index & 7;

	pte_index &= ~7UL;

	pteg_addr = get_pteg_addr(vcpu, pte_index);



	copy_from_user(pteg, (void __user *)pteg_addr, sizeof(pteg));

	hpte = pteg;



	ret = H_PTEG_FULL;

	if (likely((flags & H_EXACT) == 0)) {

		pte_index &= ~7UL;

		for (i = 0; ; ++i) {

			if (i == 8)

				return H_PTEG_FULL;

				goto done;

			if ((*hpte & HPTE_V_VALID) == 0)

				break;

			hpte += 2;

		}

	} else {

		i = kvmppc_get_gpr(vcpu, 5) & 7UL;

		hpte += i * 2;

		if (*hpte & HPTE_V_VALID)

			goto done;

	}



	hpte[0] = kvmppc_get_gpr(vcpu, 6);

	hpte[1] = kvmppc_get_gpr(vcpu, 7);

	copy_to_user((void __user *)pteg_addr, pteg, sizeof(pteg));

	kvmppc_set_gpr(vcpu, 3, H_SUCCESS);

	pteg_addr += i * HPTE_SIZE;

	copy_to_user((void __user *)pteg_addr, hpte, HPTE_SIZE);

	kvmppc_set_gpr(vcpu, 4, pte_index | i);

	ret = H_SUCCESS;



 done:

	kvmppc_set_gpr(vcpu, 3, ret);



	return EMULATE_DONE;

}