diff mbox series

[RFC,v3,17/21] hw/intc/arm_gicv3: Add NMI handling CPU interface registers

Message ID 20240223103221.1142518-18-ruanjinjie@huawei.com (mailing list archive)
State New, archived
Headers show
Series target/arm: Implement FEAT_NMI and FEAT_GICv3_NMI | expand

Commit Message

Jinjie Ruan Feb. 23, 2024, 10:32 a.m. UTC
Add the NMIAR CPU interface registers which deal with acknowledging NMI.

When introduce NMI interrupt, there are some updates to the semantics for the
register ICC_IAR1_EL1 and ICC_HPPIR1_EL1. For ICC_IAR1_EL1 register, it
should return 1022 if the intid has super priority. And for ICC_NMIAR1_EL1
register, it should return 1023 if the intid do not have super priority.
Howerever, these are not necessary for ICC_HPPIR1_EL1 register.

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
 hw/intc/arm_gicv3_cpuif.c | 46 ++++++++++++++++++++++++++++++++++++---
 hw/intc/gicv3_internal.h  |  1 +
 2 files changed, 44 insertions(+), 3 deletions(-)

Comments

Richard Henderson Feb. 23, 2024, 8:52 p.m. UTC | #1
On 2/23/24 00:32, Jinjie Ruan via wrote:
> Add the NMIAR CPU interface registers which deal with acknowledging NMI.
> 
> When introduce NMI interrupt, there are some updates to the semantics for the
> register ICC_IAR1_EL1 and ICC_HPPIR1_EL1. For ICC_IAR1_EL1 register, it
> should return 1022 if the intid has super priority. And for ICC_NMIAR1_EL1
> register, it should return 1023 if the intid do not have super priority.
> Howerever, these are not necessary for ICC_HPPIR1_EL1 register.
> 
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> ---
>   hw/intc/arm_gicv3_cpuif.c | 46 ++++++++++++++++++++++++++++++++++++---
>   hw/intc/gicv3_internal.h  |  1 +
>   2 files changed, 44 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
> index e1a60d8c15..f5bf8df32b 100644
> --- a/hw/intc/arm_gicv3_cpuif.c
> +++ b/hw/intc/arm_gicv3_cpuif.c
> @@ -1097,7 +1097,8 @@ static uint64_t icc_hppir0_value(GICv3CPUState *cs, CPUARMState *env)
>       return cs->hppi.irq;
>   }
>   
> -static uint64_t icc_hppir1_value(GICv3CPUState *cs, CPUARMState *env)
> +static uint64_t icc_hppir1_value(GICv3CPUState *cs, CPUARMState *env,
> +                                 bool is_nmi, bool is_hppi)
>   {
>       /* Return the highest priority pending interrupt register value
>        * for group 1.
> @@ -1108,6 +1109,16 @@ static uint64_t icc_hppir1_value(GICv3CPUState *cs, CPUARMState *env)
>           return INTID_SPURIOUS;
>       }
>   
> +    if (!is_hppi) {
> +        if (is_nmi && (!cs->hppi.superprio)) {
> +            return INTID_SPURIOUS;
> +        }
> +
> +        if ((!is_nmi) && cs->hppi.superprio) {
> +            return INTID_NMI;
> +        }
> +    }
> +
>       /* Check whether we can return the interrupt or if we should return
>        * a special identifier, as per the CheckGroup1ForSpecialIdentifiers
>        * pseudocode. (We can simplify a little because for us ICC_SRE_EL1.RM
> @@ -1168,7 +1179,30 @@ static uint64_t icc_iar1_read(CPUARMState *env, const ARMCPRegInfo *ri)
>       if (!icc_hppi_can_preempt(cs)) {
>           intid = INTID_SPURIOUS;
>       } else {
> -        intid = icc_hppir1_value(cs, env);
> +        intid = icc_hppir1_value(cs, env, false, false);
> +    }
> +
> +    if (!gicv3_intid_is_special(intid)) {
> +        icc_activate_irq(cs, intid);
> +    }
> +
> +    trace_gicv3_icc_iar1_read(gicv3_redist_affid(cs), intid);
> +    return intid;
> +}

This is incorrect.  For icc_iar1_read, you need something like

     if (!is_hppi
         && cs->hppi.superprio
         && env->cp15.sctlr_el[current_el] & SCTLR_NMI) {
         return INTID_NMI;
     }

I think that if SCTLR_NMI is not set, the whole system ignores Superpriority entirely, so 
returning SPURIOUS here would be incorrect.  This would make sense, letting an OS that is 
not configured for FEAT_NMI to run on ARMv8.8 hardware without modification.


> +
> +static uint64_t icc_nmiar1_read(CPUARMState *env, const ARMCPRegInfo *ri)
> +{
> +    GICv3CPUState *cs = icc_cs_from_env(env);
> +    uint64_t intid;
> +
> +    if (icv_access(env, HCR_IMO)) {
> +        return icv_iar_read(env, ri);
> +    }
> +
> +    if (!icc_hppi_can_preempt(cs)) {
> +        intid = INTID_SPURIOUS;
> +    } else {
> +        intid = icc_hppir1_value(cs, env, true, false);

Here... believe that the result *should* only consider superpriority.  I guess SPURIOUS is 
the correct result when there is no pending interrupt with superpriority?  It's really 
unclear to me from the register description.

Peter?

> @@ -2344,6 +2378,12 @@ static const ARMCPRegInfo gicv3_cpuif_reginfo[] = {
>         .access = PL1_R, .accessfn = gicv3_irq_access,
>         .readfn = icc_iar1_read,
>       },
> +    { .name = "ICC_NMIAR1_EL1", .state = ARM_CP_STATE_BOTH,
> +      .opc0 = 3, .opc1 = 0, .crn = 12, .crm = 9, .opc2 = 5,
> +      .type = ARM_CP_IO | ARM_CP_NO_RAW,
> +      .access = PL1_R, .accessfn = gicv3_irq_access,
> +      .readfn = icc_nmiar1_read,
> +    },

This register is UNDEFINED if FEAT_GICv3_NMI is not implemented.
You need to register this separately.


r~
Jinjie Ruan Feb. 26, 2024, 11:22 a.m. UTC | #2
On 2024/2/24 4:52, Richard Henderson wrote:
> On 2/23/24 00:32, Jinjie Ruan via wrote:
>> Add the NMIAR CPU interface registers which deal with acknowledging NMI.
>>
>> When introduce NMI interrupt, there are some updates to the semantics
>> for the
>> register ICC_IAR1_EL1 and ICC_HPPIR1_EL1. For ICC_IAR1_EL1 register, it
>> should return 1022 if the intid has super priority. And for
>> ICC_NMIAR1_EL1
>> register, it should return 1023 if the intid do not have super priority.
>> Howerever, these are not necessary for ICC_HPPIR1_EL1 register.
>>
>> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
>> ---
>>   hw/intc/arm_gicv3_cpuif.c | 46 ++++++++++++++++++++++++++++++++++++---
>>   hw/intc/gicv3_internal.h  |  1 +
>>   2 files changed, 44 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
>> index e1a60d8c15..f5bf8df32b 100644
>> --- a/hw/intc/arm_gicv3_cpuif.c
>> +++ b/hw/intc/arm_gicv3_cpuif.c
>> @@ -1097,7 +1097,8 @@ static uint64_t icc_hppir0_value(GICv3CPUState
>> *cs, CPUARMState *env)
>>       return cs->hppi.irq;
>>   }
>>   -static uint64_t icc_hppir1_value(GICv3CPUState *cs, CPUARMState *env)
>> +static uint64_t icc_hppir1_value(GICv3CPUState *cs, CPUARMState *env,
>> +                                 bool is_nmi, bool is_hppi)
>>   {
>>       /* Return the highest priority pending interrupt register value
>>        * for group 1.
>> @@ -1108,6 +1109,16 @@ static uint64_t icc_hppir1_value(GICv3CPUState
>> *cs, CPUARMState *env)
>>           return INTID_SPURIOUS;
>>       }
>>   +    if (!is_hppi) {
>> +        if (is_nmi && (!cs->hppi.superprio)) {
>> +            return INTID_SPURIOUS;
>> +        }
>> +
>> +        if ((!is_nmi) && cs->hppi.superprio) {
>> +            return INTID_NMI;
>> +        }
>> +    }
>> +
>>       /* Check whether we can return the interrupt or if we should return
>>        * a special identifier, as per the
>> CheckGroup1ForSpecialIdentifiers
>>        * pseudocode. (We can simplify a little because for us
>> ICC_SRE_EL1.RM
>> @@ -1168,7 +1179,30 @@ static uint64_t icc_iar1_read(CPUARMState *env,
>> const ARMCPRegInfo *ri)
>>       if (!icc_hppi_can_preempt(cs)) {
>>           intid = INTID_SPURIOUS;
>>       } else {
>> -        intid = icc_hppir1_value(cs, env);
>> +        intid = icc_hppir1_value(cs, env, false, false);
>> +    }
>> +
>> +    if (!gicv3_intid_is_special(intid)) {
>> +        icc_activate_irq(cs, intid);
>> +    }
>> +
>> +    trace_gicv3_icc_iar1_read(gicv3_redist_affid(cs), intid);
>> +    return intid;
>> +}
> 
> This is incorrect.  For icc_iar1_read, you need something like
> 
>     if (!is_hppi
>         && cs->hppi.superprio
>         && env->cp15.sctlr_el[current_el] & SCTLR_NMI) {
>         return INTID_NMI;
>     }
> 
> I think that if SCTLR_NMI is not set, the whole system ignores
> Superpriority entirely, so returning SPURIOUS here would be incorrect. 
> This would make sense, letting an OS that is not configured for FEAT_NMI
> to run on ARMv8.8 hardware without modification.

You are right. SCTLR_ELx.NMI decide whether IRQ and FIQ interrupts to
have Superpriority as an additional attribute.

> 
> 
>> +
>> +static uint64_t icc_nmiar1_read(CPUARMState *env, const ARMCPRegInfo
>> *ri)
>> +{
>> +    GICv3CPUState *cs = icc_cs_from_env(env);
>> +    uint64_t intid;
>> +
>> +    if (icv_access(env, HCR_IMO)) {
>> +        return icv_iar_read(env, ri);
>> +    }
>> +
>> +    if (!icc_hppi_can_preempt(cs)) {
>> +        intid = INTID_SPURIOUS;
>> +    } else {
>> +        intid = icc_hppir1_value(cs, env, true, false);
> 
> Here... believe that the result *should* only consider superpriority.  I
> guess SPURIOUS is the correct result when there is no pending interrupt
> with superpriority?  It's really unclear to me from the register
> description.
> 
> Peter?
> 
>> @@ -2344,6 +2378,12 @@ static const ARMCPRegInfo gicv3_cpuif_reginfo[]
>> = {
>>         .access = PL1_R, .accessfn = gicv3_irq_access,
>>         .readfn = icc_iar1_read,
>>       },
>> +    { .name = "ICC_NMIAR1_EL1", .state = ARM_CP_STATE_BOTH,
>> +      .opc0 = 3, .opc1 = 0, .crn = 12, .crm = 9, .opc2 = 5,
>> +      .type = ARM_CP_IO | ARM_CP_NO_RAW,
>> +      .access = PL1_R, .accessfn = gicv3_irq_access,
>> +      .readfn = icc_nmiar1_read,
>> +    },
> 
> This register is UNDEFINED if FEAT_GICv3_NMI is not implemented.
> You need to register this separately.
> 
> 
> r~
Peter Maydell Feb. 26, 2024, 11:32 a.m. UTC | #3
On Fri, 23 Feb 2024 at 20:53, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 2/23/24 00:32, Jinjie Ruan via wrote:
> > Add the NMIAR CPU interface registers which deal with acknowledging NMI.
> >
> > When introduce NMI interrupt, there are some updates to the semantics for the
> > register ICC_IAR1_EL1 and ICC_HPPIR1_EL1. For ICC_IAR1_EL1 register, it
> > should return 1022 if the intid has super priority. And for ICC_NMIAR1_EL1
> > register, it should return 1023 if the intid do not have super priority.
> > Howerever, these are not necessary for ICC_HPPIR1_EL1 register.
> >
> > Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>

> > +static uint64_t icc_nmiar1_read(CPUARMState *env, const ARMCPRegInfo *ri)
> > +{
> > +    GICv3CPUState *cs = icc_cs_from_env(env);
> > +    uint64_t intid;
> > +
> > +    if (icv_access(env, HCR_IMO)) {
> > +        return icv_iar_read(env, ri);
> > +    }
> > +
> > +    if (!icc_hppi_can_preempt(cs)) {
> > +        intid = INTID_SPURIOUS;
> > +    } else {
> > +        intid = icc_hppir1_value(cs, env, true, false);
>
> Here... believe that the result *should* only consider superpriority.  I guess SPURIOUS is
> the correct result when there is no pending interrupt with superpriority?  It's really
> unclear to me from the register description.

Should be 1023: the ICC_NMIAR1_EL1[] pseudocode in the GIC
architecture spec (13.1.8) does this:

    if !IsNMI(intID) then
        return ZeroExtend(INTID_SPURIOUS);

(Note that the logic is "find the highest priority
pending interrupt, and then see if it is an NMI or not",
not "find the highest priority pending NMI".)

-- PMM
diff mbox series

Patch

diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
index e1a60d8c15..f5bf8df32b 100644
--- a/hw/intc/arm_gicv3_cpuif.c
+++ b/hw/intc/arm_gicv3_cpuif.c
@@ -1097,7 +1097,8 @@  static uint64_t icc_hppir0_value(GICv3CPUState *cs, CPUARMState *env)
     return cs->hppi.irq;
 }
 
-static uint64_t icc_hppir1_value(GICv3CPUState *cs, CPUARMState *env)
+static uint64_t icc_hppir1_value(GICv3CPUState *cs, CPUARMState *env,
+                                 bool is_nmi, bool is_hppi)
 {
     /* Return the highest priority pending interrupt register value
      * for group 1.
@@ -1108,6 +1109,16 @@  static uint64_t icc_hppir1_value(GICv3CPUState *cs, CPUARMState *env)
         return INTID_SPURIOUS;
     }
 
+    if (!is_hppi) {
+        if (is_nmi && (!cs->hppi.superprio)) {
+            return INTID_SPURIOUS;
+        }
+
+        if ((!is_nmi) && cs->hppi.superprio) {
+            return INTID_NMI;
+        }
+    }
+
     /* Check whether we can return the interrupt or if we should return
      * a special identifier, as per the CheckGroup1ForSpecialIdentifiers
      * pseudocode. (We can simplify a little because for us ICC_SRE_EL1.RM
@@ -1168,7 +1179,30 @@  static uint64_t icc_iar1_read(CPUARMState *env, const ARMCPRegInfo *ri)
     if (!icc_hppi_can_preempt(cs)) {
         intid = INTID_SPURIOUS;
     } else {
-        intid = icc_hppir1_value(cs, env);
+        intid = icc_hppir1_value(cs, env, false, false);
+    }
+
+    if (!gicv3_intid_is_special(intid)) {
+        icc_activate_irq(cs, intid);
+    }
+
+    trace_gicv3_icc_iar1_read(gicv3_redist_affid(cs), intid);
+    return intid;
+}
+
+static uint64_t icc_nmiar1_read(CPUARMState *env, const ARMCPRegInfo *ri)
+{
+    GICv3CPUState *cs = icc_cs_from_env(env);
+    uint64_t intid;
+
+    if (icv_access(env, HCR_IMO)) {
+        return icv_iar_read(env, ri);
+    }
+
+    if (!icc_hppi_can_preempt(cs)) {
+        intid = INTID_SPURIOUS;
+    } else {
+        intid = icc_hppir1_value(cs, env, true, false);
     }
 
     if (!gicv3_intid_is_special(intid)) {
@@ -1555,7 +1589,7 @@  static uint64_t icc_hppir1_read(CPUARMState *env, const ARMCPRegInfo *ri)
         return icv_hppir_read(env, ri);
     }
 
-    value = icc_hppir1_value(cs, env);
+    value = icc_hppir1_value(cs, env, false, true);
     trace_gicv3_icc_hppir1_read(gicv3_redist_affid(cs), value);
     return value;
 }
@@ -2344,6 +2378,12 @@  static const ARMCPRegInfo gicv3_cpuif_reginfo[] = {
       .access = PL1_R, .accessfn = gicv3_irq_access,
       .readfn = icc_iar1_read,
     },
+    { .name = "ICC_NMIAR1_EL1", .state = ARM_CP_STATE_BOTH,
+      .opc0 = 3, .opc1 = 0, .crn = 12, .crm = 9, .opc2 = 5,
+      .type = ARM_CP_IO | ARM_CP_NO_RAW,
+      .access = PL1_R, .accessfn = gicv3_irq_access,
+      .readfn = icc_nmiar1_read,
+    },
     { .name = "ICC_EOIR1_EL1", .state = ARM_CP_STATE_BOTH,
       .opc0 = 3, .opc1 = 0, .crn = 12, .crm = 12, .opc2 = 1,
       .type = ARM_CP_IO | ARM_CP_NO_RAW,
diff --git a/hw/intc/gicv3_internal.h b/hw/intc/gicv3_internal.h
index 8d793243f4..93e56b3726 100644
--- a/hw/intc/gicv3_internal.h
+++ b/hw/intc/gicv3_internal.h
@@ -511,6 +511,7 @@  FIELD(VTE, RDBASE, 42, RDBASE_PROCNUM_LENGTH)
 /* Special interrupt IDs */
 #define INTID_SECURE 1020
 #define INTID_NONSECURE 1021
+#define INTID_NMI 1022
 #define INTID_SPURIOUS 1023
 
 /* Functions internal to the emulated GICv3 */