[Qemu-devel] [PATCH V2] target-ppc: ppc64 target's virtio can be either endian.

[Greg Kurz <gkurz@linux.vnet.ibm.com>]

We base it on the OS endian, as reflected by the endianness of the
interrupt vectors (handled through the ILE bit in the LPCR register).

This patch does two things:
- make LPCR a KVM register
- implement virtio_get_byteswap() over LPCR

Using first_cpu to fetch the registers from KVM may look arbitrary
and awkward, but it is okay because KVM sets/unsets the ILE bit on
all CPUs.

Changes in v2:
- call cpu_synchronize_state() instead of kvm_arch_get_registers().

Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
---

Alex,

If you are interested, I can resend the whole virtio+endian serie or
setup a git tree for you to pull from.

--
Greg

 target-ppc/kvm.c         |    4 ++++
 target-ppc/misc_helper.c |   12 ++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 10d0cd9..b450a22 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -869,6 +869,8 @@ int kvm_arch_put_registers(CPUState *cs, int level)
                 DPRINTF("Warning: Unable to set VPA information to KVM\n");
             }
         }
+
+        kvm_put_one_spr(cs, KVM_REG_PPC_LPCR, SPR_LPCR);
 #endif /* TARGET_PPC64 */
     }
 
@@ -1091,6 +1093,8 @@ int kvm_arch_get_registers(CPUState *cs)
                 DPRINTF("Warning: Unable to get VPA information from KVM\n");
             }
         }
+
+        kvm_get_one_spr(cs, KVM_REG_PPC_LPCR, SPR_LPCR);
 #endif
     }
 
diff --git a/target-ppc/misc_helper.c b/target-ppc/misc_helper.c
index 616aab6..e8fc8a3 100644
--- a/target-ppc/misc_helper.c
+++ b/target-ppc/misc_helper.c
@@ -20,6 +20,8 @@
 #include "helper.h"
 
 #include "helper_regs.h"
+#include "hw/virtio/virtio.h"
+#include "sysemu/kvm.h"
 
 /*****************************************************************************/
 /* SPR accesses */
@@ -116,3 +118,13 @@ void ppc_store_msr(CPUPPCState *env, target_ulong value)
 {
     hreg_store_msr(env, value, 0);
 }
+
+bool virtio_get_byteswap(void)
+{
+    PowerPCCPU *cp = POWERPC_CPU(first_cpu);
+    CPUPPCState *env = &cp->env;
+
+    cpu_synchronize_state(first_cpu);
+
+    return env->spr[SPR_LPCR] & LPCR_ILE;
+}