[PATCH] KVM: PPC: Book3S HV: ptes are big endian

[PATCH] KVM: PPC: Book3S HV: ptes are big endian

[Cédric Le Goater]

When being restored from qemu, the kvm_get_htab_header are in native
endian, but the ptes are big endian. 

This patch fixes restore on a KVM LE host. Qemu also needs a fix for
this :

     http://lists.nongnu.org/archive/html/qemu-ppc/2014-11/msg00008.html

Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Gregory Kurz <gkurz@linux.vnet.ibm.com>

---

 Tested on 3.17-rc7 with LE and BE host.

 

 arch/powerpc/kvm/book3s_64_mmu_hv.c |    2 ++
 1 file changed, 2 insertions(+)

Index: linux-3.18-hv.git/arch/powerpc/kvm/book3s_64_mmu_hv.c
===================================================================
--- linux-3.18-hv.git.orig/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ linux-3.18-hv.git/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -1542,6 +1542,8 @@ static ssize_t kvm_htab_write(struct fil
 			err = -EFAULT;
 			if (__get_user(v, lbuf) || __get_user(r, lbuf + 1))
 				goto out;
+			v = be64_to_cpu(v);
+			r = be64_to_cpu(r);
 			err = -EINVAL;
 			if (!(v & HPTE_V_VALID))
 				goto out;

Re: [PATCH] KVM: PPC: Book3S HV: ptes are big endian

[Alexander Graf]

On 03.11.14 16:35, Cédric Le Goater wrote:
> When being restored from qemu, the kvm_get_htab_header are in native
> endian, but the ptes are big endian. 
> 
> This patch fixes restore on a KVM LE host. Qemu also needs a fix for
> this :
> 
>      http://lists.nongnu.org/archive/html/qemu-ppc/2014-11/msg00008.html
> 
> Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
> Cc: Gregory Kurz <gkurz@linux.vnet.ibm.com>
> 
> ---
> 
>  Tested on 3.17-rc7 with LE and BE host.
> 
>  
> 
>  arch/powerpc/kvm/book3s_64_mmu_hv.c |    2 ++
>  1 file changed, 2 insertions(+)
> 
> Index: linux-3.18-hv.git/arch/powerpc/kvm/book3s_64_mmu_hv.c
> ===================================================================
> --- linux-3.18-hv.git.orig/arch/powerpc/kvm/book3s_64_mmu_hv.c
> +++ linux-3.18-hv.git/arch/powerpc/kvm/book3s_64_mmu_hv.c
> @@ -1542,6 +1542,8 @@ static ssize_t kvm_htab_write(struct fil
>  			err = -EFAULT;
>  			if (__get_user(v, lbuf) || __get_user(r, lbuf + 1))
>  				goto out;
> +			v = be64_to_cpu(v);
> +			r = be64_to_cpu(r);

This will trigger warnings with sparse. Please introduce new be64
variables that you do get_user on and that you then use as source for v
and r.


Alex

[PATCH v2] KVM: PPC: Book3S HV: ptes are big endian

[Cédric Le Goater]

When being restored from qemu, the kvm_get_htab_header are in native
endian, but the ptes are big endian. 

This patch fixes restore on a KVM LE host. Qemu also needs a fix for
this :

     http://lists.nongnu.org/archive/html/qemu-ppc/2014-11/msg00008.html

Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Gregory Kurz <gkurz@linux.vnet.ibm.com>

---

Tested on 3.18-rc5 with LE and BE host.

v2: add be64 local variables to be friendly with sparse
 

 arch/powerpc/kvm/book3s_64_mmu_hv.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Index: linux-3.18-hv.git/arch/powerpc/kvm/book3s_64_mmu_hv.c
===================================================================
--- linux-3.18-hv.git.orig/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ linux-3.18-hv.git/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -1539,9 +1539,15 @@ static ssize_t kvm_htab_write(struct fil
 		hptp = (__be64 *)(kvm->arch.hpt_virt + (i * HPTE_SIZE));
 		lbuf = (unsigned long __user *)buf;
 		for (j = 0; j < hdr.n_valid; ++j) {
+			__be64 hpte_v;
+			__be64 hpte_r;
+
 			err = -EFAULT;
-			if (__get_user(v, lbuf) || __get_user(r, lbuf + 1))
+			if (__get_user(hpte_v, lbuf) ||
+			    __get_user(hpte_r, lbuf + 1))
 				goto out;
+			v = be64_to_cpu(hpte_v);
+			r = be64_to_cpu(hpte_r);
 			err = -EINVAL;
 			if (!(v & HPTE_V_VALID))
 				goto out;

Re: [PATCH v2] KVM: PPC: Book3S HV: ptes are big endian

[Alexander Graf]

On 21.11.14 00:45, Cédric Le Goater wrote:
> When being restored from qemu, the kvm_get_htab_header are in native
> endian, but the ptes are big endian. 
> 
> This patch fixes restore on a KVM LE host. Qemu also needs a fix for
> this :
> 
>      http://lists.nongnu.org/archive/html/qemu-ppc/2014-11/msg00008.html
> 
> Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
> Cc: Gregory Kurz <gkurz@linux.vnet.ibm.com>

Thanks, applied to kvm-ppc-queue.


Alex