Re: [PATCH 14/31] KVM: arm64: vgic-v3: Add ICV_EOIR1_EL1 handler

Marc Zyngier
2017-05-30T14:20:53Z

On 30/05/17 08:48, Auger Eric wrote:
> Hi Marc
>
> On 03/05/2017 12:45, Marc Zyngier wrote:
>> Add a handler for writing the guest's view of the ICC_EOIR1_EL1
>> register. This involves dropping the priority of the interrupt,
>> and deactivating it if required (EOImode == 0).
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>> ---
>> include/linux/irqchip/arm-gic-v3.h | 2 +
>> virt/kvm/arm/hyp/vgic-v3-sr.c | 119 +++++++++++++++++++++++++++++++++++++
>> 2 files changed, 121 insertions(+)
>>
>> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
>> index 7610ea4e8337..c56d9bc2c904 100644
>> --- a/include/linux/irqchip/arm-gic-v3.h
>> +++ b/include/linux/irqchip/arm-gic-v3.h
>> @@ -403,6 +403,8 @@
>>
>> #define ICH_HCR_EN (1 << 0)
>> #define ICH_HCR_UIE (1 << 1)
>> +#define ICH_HCR_EOIcount_SHIFT 27
>> +#define ICH_HCR_EOIcount_MASK (0x1f << ICH_HCR_EOIcount_SHIFT)
>>
>> #define ICH_VMCR_CBPR_SHIFT 4
>> #define ICH_VMCR_CBPR_MASK (1 << ICH_VMCR_CBPR_SHIFT)
>> diff --git a/virt/kvm/arm/hyp/vgic-v3-sr.c b/virt/kvm/arm/hyp/vgic-v3-sr.c
>> index 49aad1de3ac8..a76351b3ad66 100644
>> --- a/virt/kvm/arm/hyp/vgic-v3-sr.c
>> +++ b/virt/kvm/arm/hyp/vgic-v3-sr.c
>> @@ -425,6 +425,26 @@ static int __hyp_text __vgic_v3_highest_priority_lr(struct kvm_vcpu *vcpu,
>> return lr;
>> }
>>
>> +static int __hyp_text __vgic_v3_find_active_lr(struct kvm_vcpu *vcpu,
>> + int intid, u64 *lr_val)
>> +{
>> + unsigned int used_lrs = vcpu->arch.vgic_cpu.used_lrs;
>> + int i;
>> +
>> + for (i = 0; i < used_lrs; i++) {
>> + u64 val = __gic_v3_get_lr(i);
>> +
>> + if ((val & ICH_LR_VIRTUAL_ID_MASK) == intid &&
>> + (val & ICH_LR_ACTIVE_BIT)) {
> I guess it is safe because we don't have yet virtual interrupts directly
> mapped to phys IRQs, besides timer one?

What would that change? I don't see how having a HW interrupt here would
be unsafe... Am I missing something?

>> + *lr_val = val;
>> + return i;
>> + }
>> + }
>> +
>> + *lr_val = ICC_IAR1_EL1_SPURIOUS;
>> + return -1;
>> +}
>> +
>> static int __hyp_text __vgic_v3_get_highest_active_priority(void)
>> {
>> u8 nr_pre_bits = vtr_to_nr_pre_bits(read_gicreg(ICH_VTR_EL2));
>> @@ -490,6 +510,44 @@ static void __hyp_text __vgic_v3_set_active_priority(u8 pre)
>> __vgic_v3_write_ap1rn(val | bit, apr);
>> }
>>
>> +static int __hyp_text __vgic_v3_clear_highest_active_priority(void)
>> +{
>> + u8 nr_pre_bits = vtr_to_nr_pre_bits(read_gicreg(ICH_VTR_EL2));
>> + u8 nr_aprs = 1 << (nr_pre_bits - 5);
> may be worth to introduce a macro to compute the number of APRn regs.
> This may be more understandable.

Sure, will do.

>> + u32 hap = 0;
>> + int i;
>> +
>> + for (i = 0; i < nr_aprs; i++) {
>> + u32 ap0, ap1;
>> + int c0, c1;
>> +
>> + ap0 = __vgic_v3_read_ap0rn(i);
>> + ap1 = __vgic_v3_read_ap1rn(i);
>> + if (!ap0 && !ap1) {
>> + hap += 32;
>> + continue;
>> + }
>> +
>> + c0 = ap0 ? __ffs(ap0) : 32;
>> + c1 = ap1 ? __ffs(ap1) : 32;
>> +
>> + /* Always clear the LSB, which is the highest priority */
>> + if (c0 < c1) {
>> + ap0 &= ap0 - 1;
>> + __vgic_v3_write_ap0rn(ap0, i);
>> + hap += c0;
>> + } else {
>> + ap1 &= ap1 - 1;
>> + __vgic_v3_write_ap1rn(ap1, i);
>> + hap += c1;
>> + }
>> +
>> + return hap << (8 - nr_pre_bits);
>> + }
>> +
>> + return GICv3_IDLE_PRIORITY;
>> +}
>> +
>> static void __hyp_text __vgic_v3_read_iar(struct kvm_vcpu *vcpu, u32 vmcr, int rt)
>> {
>> u64 lr_val;
>> @@ -526,6 +584,64 @@ static void __hyp_text __vgic_v3_read_iar(struct kvm_vcpu *vcpu, u32 vmcr, int r
>> vcpu_set_reg(vcpu, rt, ICC_IAR1_EL1_SPURIOUS);
>> }
>>
>> +static void __hyp_text __vgic_v3_clear_active_lr(int lr, u64 lr_val)
>> +{
>> + lr_val &= ~ICH_LR_ACTIVE_BIT;
>> + if (lr_val & ICH_LR_HW) {
>> + u32 pid;
> nit: insert a line

OK.

>> + pid = (lr_val & ICH_LR_PHYS_ID_MASK) >> ICH_LR_PHYS_ID_SHIFT;
>> + gic_write_dir(pid);
>> + }
>> +
>> + __gic_v3_set_lr(lr_val, lr);
>> +}
>> +
>> +static void __hyp_text __vgic_v3_bump_eoicount(void)
>> +{
>> + u32 hcr;
>> +
>> + hcr = read_gicreg(ICH_HCR_EL2);
>> + hcr += 1 << ICH_HCR_EOIcount_SHIFT;
>> + write_gicreg(hcr, ICH_HCR_EL2);
>> +}
>> +
>> +static void __hyp_text __vgic_v3_write_eoir(struct kvm_vcpu *vcpu, u32 vmcr, int rt)
>> +{
>> + u32 vid = vcpu_get_reg(vcpu, rt);
>> + u64 lr_val;
>> + u8 lr_prio, act_prio;
>> + int lr, grp;
>> +
>> + grp = __vgic_v3_get_group(vcpu);
>> +
>> + /* Drop priority in any case */
>> + act_prio = __vgic_v3_clear_highest_active_priority();
>> +
>> + /* If EOIing an LPI, no deactivate to be performed */
>> + if (vid >= VGIC_MIN_LPI)
>> + return;
>> +
>> + /* EOImode == 1, nothing to be done here */
>> + if (vmcr & ICH_VMCR_EOIM_MASK)
>> + return;
>> +
>> + lr = __vgic_v3_find_active_lr(vcpu, vid, &lr_val);
>> + if (lr == -1) {
>> + __vgic_v3_bump_eoicount();
>> + return;
>> + }
>> +
>> + lr_prio = (lr_val & ICH_LR_PRIORITY_MASK) >> ICH_LR_PRIORITY_SHIFT;
>> +
>> + /* If priorities or group do not match, the guest has fscked-up. */
>> + if (grp != !!(lr_val & ICH_LR_GROUP) ||
>> + __vgic_v3_pri_to_pre(lr_prio, vmcr, grp) != act_prio)
>> + return;
>> +
>> + /* Let's now perform the deactivation */
>> + __vgic_v3_clear_active_lr(lr, lr_val);
>> +}
>> +
>> static void __hyp_text __vgic_v3_read_igrpen1(struct kvm_vcpu *vcpu, u32 vmcr, int rt)
>> {
>> vcpu_set_reg(vcpu, rt, !!(vmcr & ICH_VMCR_ENG1_MASK));
>> @@ -591,6 +707,9 @@ int __hyp_text __vgic_v3_perform_cpuif_access(struct kvm_vcpu *vcpu)
>> case SYS_ICC_IAR1_EL1:
>> fn = __vgic_v3_read_iar;
>> break;
>> + case SYS_ICC_EOIR1_EL1:
>> + fn = __vgic_v3_write_eoir;
>> + break;
>> case SYS_ICC_GRPEN1_EL1:
>> if (is_read)
>> fn = __vgic_v3_read_igrpen1;
>
> Looks good to me
>
> Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks!

M.
--
Jazz is not dead. It just smells funny...