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KVM: PPC: Book3S PR: Correct errors in H_ENTER implementation

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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: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
Paul Mackerras 2013-09-20 14:52:47 +10:00 committed by Alexander Graf
parent 03a9c90334
commit 5cd92a9521
1 changed files with 14 additions and 5 deletions
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19
arch/powerpc/kvm/book3s_pr_papr.c
View file

@ -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;
}