Re: [Qemu-devel] [PATCH] target-ppc: ppc64 target's virtio can be either endian. (v3)

[Alexander Graf]

On 17.01.2014, at 14:52, Greg Kurz gk...@linux.vnet.ibm.com wrote:

 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 implements 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 v3:
 -  dropped the explicit calls to kvm_[get|put]_one_reg as LPCR is
   now properly handled by the generic SPR code.
 Changes in v2:
 - call cpu_synchronize_state() instead of kvm_arch_get_registers().
 
 Suggested-by: Benjamin Herrenschmidt b...@kernel.crashing.org
 Signed-off-by: Rusty Russell ru...@rustcorp.com.au
 Signed-off-by: Greg Kurz gk...@linux.vnet.ibm.com
 Reviewed-by: Alexander Graf ag...@suse.de
 ---
 target-ppc/misc_helper.c |   12 
 1 file changed, 12 insertions(+)
 
 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);

LPCR_ILE only gets modified by QEMU, so you can even get rid of the synchronize 
call :).

Either way, this can only go in after the generic virtio byteswap mechanics are 
merged.


Alex

 +
 +return env-spr[SPR_LPCR]  LPCR_ILE;
 +}
 

[Qemu-devel] [PATCH] target-ppc: ppc64 target's virtio can be either endian. (v3)

[Greg Kurz]

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 implements 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 v3:
-  dropped the explicit calls to kvm_[get|put]_one_reg as LPCR is
   now properly handled by the generic SPR code.
Changes in v2:
- call cpu_synchronize_state() instead of kvm_arch_get_registers().

Suggested-by: Benjamin Herrenschmidt b...@kernel.crashing.org
Signed-off-by: Rusty Russell ru...@rustcorp.com.au
Signed-off-by: Greg Kurz gk...@linux.vnet.ibm.com
Reviewed-by: Alexander Graf ag...@suse.de
---
 target-ppc/misc_helper.c |   12 
 1 file changed, 12 insertions(+)

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;
+}