On Thu, May 15, 2014 at 09:09:05PM +0800, Haojian Zhuang wrote:

On 15 May 2014 17:42, Marc Zyngier [off-list ref] wrote:

quoted

On 11/05/14 09:06, Haojian Zhuang wrote:

quoted

In ARM standard GIC, GICH_APR offset is 0xf0 & GICH_LR0 offset is 0x100.
In HiP04 GIC, GICH_APR offset is 0x70 & GICH_LR0 offset is 0x80.

Now reuse the nr_lr field in struct vgic_cpu. Bit[31:16] is used to store
GICH_APR offset in HiP04, and bit[15:0] is used to store real nr_lr
variable. In ARM standard GIC, don't set bit[31:16]. So we could avoid
to change the VGIC implementation in arm64.

Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>
---
 arch/arm/kvm/interrupts_head.S  | 32 ++++++++++++++++++++++------
 include/kvm/arm_vgic.h          |  5 ++++-
 include/linux/irqchip/arm-gic.h |  6 ++++++
 virt/kvm/arm/vgic.c             | 47 +++++++++++++++++++++++++++++------------
 4 files changed, 69 insertions(+), 21 deletions(-)

diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S
index 76af9302..7aacaff 100644
--- a/arch/arm/kvm/interrupts_head.S
+++ b/arch/arm/kvm/interrupts_head.S

@@ -419,7 +419,10 @@ vcpu     .req    r0              @ vcpu pointer always in r0
      ldr     r7, [r2, #GICH_EISR1]
      ldr     r8, [r2, #GICH_ELRSR0]
      ldr     r9, [r2, #GICH_ELRSR1]
-     ldr     r10, [r2, #GICH_APR]
+     ldr     r10, [r11, #VGIC_CPU_NR_LR]

Please rename this field to something else, now that it contains more
than the number of LRs.

Since vgic driver is shared between arm & arm64, I only use high word
in VGIC_CPU_NR_LR register if SoC is HiP04. Then I could avoid to
change the vgic implementation in arm64.

Do you want to me change arm64 implementation at the same time?

quoted

quoted

+     movs    r10, r10, lsr #HWCFG_APR_SHIFT
+     ldrne   r10, [r2, r10]
+     ldreq   r10, [r2, #GICH_APR]

No. Just encode the offset there always. No need for a test.

We don't want all these conditionals in the critical path and it makes
the code impossible to read, please follow Marc's advice.

Thanks,
-Christoffer