[PULL 14/41] KVM: PPC: Book3S PR: Do dcbz32 patching with big endian instructions

Alexander Graf
2014-05-30T12:43:03Z

When the host CPU we're running on doesn't support dcbz32 itself, but the
guest wants to have dcbz only clear 32 bytes of data, we loop through every
executable mapped page to search for dcbz instructions and patch them with
a special privileged instruction that we emulate as dcbz32.

The only guests that want to see dcbz act as 32byte are book3s_32 guests, so
we don't have to worry about little endian instruction ordering. So let's
just always search for big endian dcbz instructions, also when we're on a
little endian host.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
arch/powerpc/kvm/book3s_32_mmu.c | 2 +-
arch/powerpc/kvm/book3s_pr.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_32_mmu.c b/arch/powerpc/kvm/book3s_32_mmu.c
index 628d90e..93503bb 100644
--- a/arch/powerpc/kvm/book3s_32_mmu.c
+++ b/arch/powerpc/kvm/book3s_32_mmu.c
@@ -131,7 +131,7 @@ static hva_t kvmppc_mmu_book3s_32_get_pteg(struct kvm_vcpu *vcpu,
pteg = (vcpu_book3s->sdr1 & 0xffff0000) | hash;

dprintk("MMU: pc=0x%lx eaddr=0x%lx sdr1=0x%llx pteg=0x%x vsid=0x%x\n",
- kvmppc_get_pc(&vcpu_book3s->vcpu), eaddr, vcpu_book3s->sdr1, pteg,
+ kvmppc_get_pc(vcpu), eaddr, vcpu_book3s->sdr1, pteg,
sr_vsid(sre));

r = gfn_to_hva(vcpu->kvm, pteg >> PAGE_SHIFT);
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index d424ca0..6e55934 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -428,8 +428,8 @@ static void kvmppc_patch_dcbz(struct kvm_vcpu *vcpu, struct kvmppc_pte *pte)

/* patch dcbz into reserved instruction, so we trap */
for (i=hpage_offset; i < hpage_offset + (HW_PAGE_SIZE / 4); i++)
- if ((page[i] & 0xff0007ff) == INS_DCBZ)
- page[i] &= 0xfffffff7;
+ if ((be32_to_cpu(page[i]) & 0xff0007ff) == INS_DCBZ)
+ page[i] &= cpu_to_be32(0xfffffff7);

kunmap_atomic(page);
put_page(hpage);
--
1.8.1.4