Re: [PATCH 5/6 v2] KVM: PPC: Book3E: Add ONE_REG AltiVec support

[Alexander Graf]

On 03.07.14 18:11, mihai.cara...@freescale.com wrote:

-Original Message-
From: Alexander Graf [mailto:ag...@suse.de]
Sent: Thursday, July 03, 2014 3:34 PM
To: Caraman Mihai Claudiu-B02008; kvm-ppc@vger.kernel.org
Cc: k...@vger.kernel.org; linuxppc-...@lists.ozlabs.org
Subject: Re: [PATCH 5/6 v2] KVM: PPC: Book3E: Add ONE_REG AltiVec support


On 30.06.14 17:34, Mihai Caraman wrote:

Add ONE_REG support for AltiVec on Book3E.

Signed-off-by: Mihai Caraman mihai.cara...@freescale.com

Any chance we can handle these in generic code?

I expected this request :) Can we let this for a second phase to have
e6500 enabled first?


I don't see the value of duplicating code in e500 specific code only to 
remove and combine it in common code in a follow-up patch after that.



Can you share with us a Book3S setup so I can validate the requested
changes? I already fell anxious touching strange hardware specific
Book3S code without running it.


Until a few weeks ago I had an externally reachable G5 machine that we 
could've used for this. Unfortunately I had to replace the box with 
another one that's not quite as stable. I'll try and see if I can fix or 
replace it soon.



Alex

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RE: [PATCH 5/6 v2] KVM: PPC: Book3E: Add ONE_REG AltiVec support

[mihai.cara...@freescale.com]

 -Original Message-
 From: Alexander Graf [mailto:ag...@suse.de]
 Sent: Thursday, July 03, 2014 3:34 PM
 To: Caraman Mihai Claudiu-B02008; kvm-ppc@vger.kernel.org
 Cc: k...@vger.kernel.org; linuxppc-...@lists.ozlabs.org
 Subject: Re: [PATCH 5/6 v2] KVM: PPC: Book3E: Add ONE_REG AltiVec support
 
 
 On 30.06.14 17:34, Mihai Caraman wrote:
  Add ONE_REG support for AltiVec on Book3E.
 
  Signed-off-by: Mihai Caraman mihai.cara...@freescale.com
 
 Any chance we can handle these in generic code?

I expected this request :) Can we let this for a second phase to have
e6500 enabled first?

Can you share with us a Book3S setup so I can validate the requested
changes? I already fell anxious touching strange hardware specific
Book3S code without running it.

-Mike
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[PATCH 5/6 v2] KVM: PPC: Book3E: Add ONE_REG AltiVec support

[Mihai Caraman]

Add ONE_REG support for AltiVec on Book3E.

Signed-off-by: Mihai Caraman mihai.cara...@freescale.com
---
v2:
 - add comment describing VCSR register representation in KVM vs kernel

 arch/powerpc/include/uapi/asm/kvm.h |  5 +
 arch/powerpc/kvm/booke.c| 34 ++
 2 files changed, 39 insertions(+)

diff --git a/arch/powerpc/include/uapi/asm/kvm.h 
b/arch/powerpc/include/uapi/asm/kvm.h
index 2bc4a94..3adbce4 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -476,6 +476,11 @@ struct kvm_get_htab_header {
 
 /* FP and vector status/control registers */
 #define KVM_REG_PPC_FPSCR  (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x80)
+/*
+ * VSCR register is documented as a 32-bit register in the ISA, but it can
+ * only be accesses via a vector register. Expose VSCR as a 32-bit register
+ * even though the kernel represents it as a 128-bit vector.
+ */
 #define KVM_REG_PPC_VSCR   (KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x81)
 
 /* Virtual processor areas */
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 4ba75f6..fe15a94 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -1634,6 +1634,23 @@ int kvm_vcpu_ioctl_get_one_reg(struct kvm_vcpu *vcpu, 
struct kvm_one_reg *reg)
case KVM_REG_PPC_VRSAVE:
val = get_reg_val(reg-id, vcpu-arch.vrsave);
break;
+#ifdef CONFIG_ALTIVEC
+   case KVM_REG_PPC_VR0 ... KVM_REG_PPC_VR31:
+   if (!cpu_has_feature(CPU_FTR_ALTIVEC)) {
+   r = -ENXIO;
+   break;
+   }
+   val.vval = vcpu-arch.vr.vr[reg-id - KVM_REG_PPC_VR0];
+   break;
+   case KVM_REG_PPC_VSCR:
+   if (!cpu_has_feature(CPU_FTR_ALTIVEC)) {
+   r = -ENXIO;
+   break;
+   }
+   val = get_reg_val(reg-id, vcpu-arch.vr.vscr.u[3]);
+   break;
+#endif /* CONFIG_ALTIVEC */
+
default:
r = vcpu-kvm-arch.kvm_ops-get_one_reg(vcpu, reg-id, val);
break;
@@ -1717,6 +1734,23 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, 
struct kvm_one_reg *reg)
case KVM_REG_PPC_VRSAVE:
vcpu-arch.vrsave = set_reg_val(reg-id, val);
break;
+#ifdef CONFIG_ALTIVEC
+   case KVM_REG_PPC_VR0 ... KVM_REG_PPC_VR31:
+   if (!cpu_has_feature(CPU_FTR_ALTIVEC)) {
+   r = -ENXIO;
+   break;
+   }
+   vcpu-arch.vr.vr[reg-id - KVM_REG_PPC_VR0] = val.vval;
+   break;
+   case KVM_REG_PPC_VSCR:
+   if (!cpu_has_feature(CPU_FTR_ALTIVEC)) {
+   r = -ENXIO;
+   break;
+   }
+   vcpu-arch.vr.vscr.u[3] = set_reg_val(reg-id, val);
+   break;
+#endif /* CONFIG_ALTIVEC */
+
default:
r = vcpu-kvm-arch.kvm_ops-set_one_reg(vcpu, reg-id, val);
break;
-- 
1.7.11.7

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