Re: [Qemu-devel] [PATCH v2 2/2] arm_gicv3_kvm: kvm_dist_get/put: skip the registers banked by GICR

[Shannon Zhao <zhaoshenglong@huawei.com>]

On 2018/3/20 16:42, Auger Eric wrote:
> Hi Shannon,
> On 20/03/18 08:26, Shannon Zhao wrote:
>> While we skip the GIC_INTERNAL irqs, we don't change the register offset
>> accordingly. This will overlap the GICR registers value and leave the
>> last GIC_INTERNAL irq's registers out of update.
>>
>> Fix this by skipping the registers banked by GICR.
>>
>> Signed-off-by: Shannon Zhao <zhaoshenglong@huawei.com>
>> ---
>>  hw/intc/arm_gicv3_kvm.c | 38 ++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 38 insertions(+)
>>
>> diff --git a/hw/intc/arm_gicv3_kvm.c b/hw/intc/arm_gicv3_kvm.c
>> index 3536795..d423cba 100644
>> --- a/hw/intc/arm_gicv3_kvm.c
>> +++ b/hw/intc/arm_gicv3_kvm.c
>> @@ -136,6 +136,12 @@ static void kvm_dist_get_priority(GICv3State *s, uint32_t offset, uint8_t *bmp)
>>      int irq;
>>  
>>      field = (uint32_t *)bmp;
>> +    /* For the KVM GICv3, affinity routing is always enabled, and the first 8
>> +     * GICD_IPRIORITYR<n> registers are always RAZ/WI. The corresponding
>> +     * functionality is replaced by GICR_IPRIORITYR<n>. So it doesn't need to
>> +     * sync them.
>> +     */
>> +    offset += (8 * sizeof(uint32_t));
>>      for_each_dist_irq_reg(irq, s->num_irq, 8) {
>>          kvm_gicd_access(s, offset, &reg, false);
>>          *field = reg;
>> @@ -150,6 +156,12 @@ static void kvm_dist_put_priority(GICv3State *s, uint32_t offset, uint8_t *bmp)
>>      int irq;
>>  
>>      field = (uint32_t *)bmp;
>> +    /* For the KVM GICv3, affinity routing is always enabled, and the first 8
>> +     * GICD_IPRIORITYR<n> registers are always RAZ/WI. The corresponding
>> +     * functionality is replaced by GICR_IPRIORITYR<n>. So it doesn't need to
>> +     * sync them.
>> +     */
>> +    offset += (8 * sizeof(uint32_t));
>>      for_each_dist_irq_reg(irq, s->num_irq, 8) {
>>          reg = *field;
>>          kvm_gicd_access(s, offset, &reg, true);
>> @@ -164,6 +176,12 @@ static void kvm_dist_get_edge_trigger(GICv3State *s, uint32_t offset,
>>      uint32_t reg;
>>      int irq;
>>  
>> +    /* For the KVM GICv3, affinity routing is always enabled, and the first 2
>> +     * GICD_ICFGR<n> registers are always RAZ/WI. The corresponding
>> +     * functionality is replaced by GICR_ICFGR<n>. So it doesn't need to sync
>> +     * them.
>> +     */
>> +    offset += (2 * sizeof(uint32_t));
>>      for_each_dist_irq_reg(irq, s->num_irq, 2) {
>>          kvm_gicd_access(s, offset, &reg, false);
>>          reg = half_unshuffle32(reg >> 1);
>> @@ -181,6 +199,12 @@ static void kvm_dist_put_edge_trigger(GICv3State *s, uint32_t offset,
>>      uint32_t reg;
>>      int irq;
>>  
>> +    /* For the KVM GICv3, affinity routing is always enabled, and the first 2
>> +     * GICD_ICFGR<n> registers are always RAZ/WI. The corresponding
>> +     * functionality is replaced by GICR_ICFGR<n>. So it doesn't need to sync
>> +     * them.
>> +     */
>> +    offset += (2 * sizeof(uint32_t));
>>      for_each_dist_irq_reg(irq, s->num_irq, 2) {
>>          reg = *gic_bmp_ptr32(bmp, irq);
>>          if (irq % 32 != 0) {
>> @@ -222,6 +246,12 @@ static void kvm_dist_getbmp(GICv3State *s, uint32_t offset, uint32_t *bmp)
>>      uint32_t reg;
>>      int irq;
>>  
>> +    /* For the KVM GICv3, affinity routing is always enabled, and the
>> +     * GICD_IGROUPR0/GICD_ISENABLER0/GICD_ISPENDR0/GICD_ISACTIVER0 registers
>> +     * are always RAZ/WI. The corresponding functionality is replaced by the
>> +     * GICR registers. So it doesn't need to sync them.
>> +     */
>> +    offset += (1 * sizeof(uint32_t));
>>      for_each_dist_irq_reg(irq, s->num_irq, 1) {
>>          kvm_gicd_access(s, offset, &reg, false);
>>          *gic_bmp_ptr32(bmp, irq) = reg;
>> @@ -235,6 +265,14 @@ static void kvm_dist_putbmp(GICv3State *s, uint32_t offset,
>>      uint32_t reg;
>>      int irq;
>>  
>> +    /* For the KVM GICv3, affinity routing is always enabled, and the
>> +     * GICD_IGROUPR0/GICD_ISENABLER0/GICD_ISPENDR0/GICD_ISACTIVER0 registers
>> +     * are always RAZ/WI. The corresponding functionality is replaced by the
>> +     * GICR registers. So it doesn't need to sync them.
>> +     */
>> +    offset += (1 * sizeof(uint32_t));
> I wonder we couldn't create a new for_each_dist_irq_reg() macro taking
> the offset and clroffset and integrating that shift inside?
> 
Peter, what's your opinion?

>> +    if (clroffset != 0)
> nit style issue: brace needed here
>
OK

> Besides Reviewed-by: Eric Auger <eric.auger@redhat.com>
> 
Thanks!

> Thanks
> 
> Eric
> 
>> +        clroffset += (1 * sizeof(uint32_t));
>>      for_each_dist_irq_reg(irq, s->num_irq, 1) {
>>          /* If this bitmap is a set/clear register pair, first write to the
>>           * clear-reg to clear all bits before using the set-reg to write
>>
> 
> .
> 

-- 
Shannon