diff mbox series

[v1,3/9] hw/intc/gic: use MxTxAttrs to divine accessing CPU

Message ID 20220922145832.1934429-4-alex.bennee@linaro.org
State Superseded
Headers show
Series MemTxAttrs cpu_index and gdbstub/next | expand

Commit Message

Alex Bennée Sept. 22, 2022, 2:58 p.m. UTC
Now that MxTxAttrs encodes a CPU we should use that to figure it out.
This solves edge cases like accessing via gdbstub or qtest.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/124

---
v2
  - update for new field
  - bool asserts
---
 hw/intc/arm_gic.c | 39 ++++++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 17 deletions(-)

Comments

Richard Henderson Sept. 25, 2022, 10:11 a.m. UTC | #1
On 9/22/22 14:58, Alex Bennée wrote:
> Now that MxTxAttrs encodes a CPU we should use that to figure it out.
> This solves edge cases like accessing via gdbstub or qtest.
> 
> Signed-off-by: Alex Bennée<alex.bennee@linaro.org>
> Resolves:https://gitlab.com/qemu-project/qemu/-/issues/124
> 
> ---

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~
Mads Ynddal Sept. 26, 2022, 10:56 a.m. UTC | #2
> On 22 Sep 2022, at 16.58, Alex Bennée <alex.bennee@linaro.org> wrote:
> 
> Now that MxTxAttrs encodes a CPU we should use that to figure it out.
> This solves edge cases like accessing via gdbstub or qtest.
> 
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/124
> 
> ---
> v2
>  - update for new field
>  - bool asserts
> ---
> hw/intc/arm_gic.c | 39 ++++++++++++++++++++++-----------------
> 1 file changed, 22 insertions(+), 17 deletions(-)
> 
> diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
> index 492b2421ab..b58d3c4a95 100644
> --- a/hw/intc/arm_gic.c
> +++ b/hw/intc/arm_gic.c
> @@ -56,17 +56,22 @@ static const uint8_t gic_id_gicv2[] = {
>     0x04, 0x00, 0x00, 0x00, 0x90, 0xb4, 0x2b, 0x00, 0x0d, 0xf0, 0x05, 0xb1
> };
> 
> -static inline int gic_get_current_cpu(GICState *s)
> +static inline int gic_get_current_cpu(GICState *s, MemTxAttrs attrs)
> {
> -    if (!qtest_enabled() && s->num_cpu > 1) {
> -        return current_cpu->cpu_index;
> -    }
> -    return 0;
> +    /*
> +     * Something other than a CPU accessing the GIC would be a bug as
> +     * would a CPU index higher than the GICState expects to be
> +     * handling
> +     */
> +    g_assert(attrs.requester_is_cpu);
> +    g_assert(attrs.cpu_index < s->num_cpu);
> +
> +    return attrs.requester_id;
> }

The asserts here abort on macOS, with HVF accelerator:

ERROR:../hw/intc/arm_gic.c:66:gic_get_current_cpu: assertion failed: (attrs.requester_is_cpu)
Bail out! ERROR:../hw/intc/arm_gic.c:66:gic_get_current_cpu: assertion failed: (attrs.requester_is_cpu)

If I revert the changes inside this function, it seemingly works again.
Alex Bennée Sept. 26, 2022, 11:01 a.m. UTC | #3
mads@ynddal.dk writes:

>> On 22 Sep 2022, at 16.58, Alex Bennée <alex.bennee@linaro.org> wrote:
>> 
>> Now that MxTxAttrs encodes a CPU we should use that to figure it out.
>> This solves edge cases like accessing via gdbstub or qtest.
>> 
>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/124
>> 
>> ---
>> v2
>>  - update for new field
>>  - bool asserts
>> ---
>> hw/intc/arm_gic.c | 39 ++++++++++++++++++++++-----------------
>> 1 file changed, 22 insertions(+), 17 deletions(-)
>> 
>> diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
>> index 492b2421ab..b58d3c4a95 100644
>> --- a/hw/intc/arm_gic.c
>> +++ b/hw/intc/arm_gic.c
>> @@ -56,17 +56,22 @@ static const uint8_t gic_id_gicv2[] = {
>>     0x04, 0x00, 0x00, 0x00, 0x90, 0xb4, 0x2b, 0x00, 0x0d, 0xf0, 0x05, 0xb1
>> };
>> 
>> -static inline int gic_get_current_cpu(GICState *s)
>> +static inline int gic_get_current_cpu(GICState *s, MemTxAttrs attrs)
>> {
>> -    if (!qtest_enabled() && s->num_cpu > 1) {
>> -        return current_cpu->cpu_index;
>> -    }
>> -    return 0;
>> +    /*
>> +     * Something other than a CPU accessing the GIC would be a bug as
>> +     * would a CPU index higher than the GICState expects to be
>> +     * handling
>> +     */
>> +    g_assert(attrs.requester_is_cpu);
>> +    g_assert(attrs.cpu_index < s->num_cpu);
>> +
>> +    return attrs.requester_id;
>> }
>
> The asserts here abort on macOS, with HVF accelerator:
>
> ERROR:../hw/intc/arm_gic.c:66:gic_get_current_cpu: assertion failed: (attrs.requester_is_cpu)
> Bail out! ERROR:../hw/intc/arm_gic.c:66:gic_get_current_cpu: assertion failed: (attrs.requester_is_cpu)
>
> If I revert the changes inside this function, it seemingly works
> again.

Thanks for testing.

I guess this is because the we have a soft GIC for HVF. Somewhere in the
hvf code path we must encode up an MemTxAttrs when the gic is accessed.

Could you try in the EC_DATAABORT path in
target/arm/hvf/hvf.c:hvf_vcpu_exec:

        if (iswrite) {
            val = hvf_get_reg(cpu, srt);
            address_space_write(&address_space_memory,
                                hvf_exit->exception.physical_address,
                                MEMTXATTRS_CPU(cpu->cpu_index), &val, len);
        } else {
            address_space_read(&address_space_memory,
                               hvf_exit->exception.physical_address,
                               MEMTXATTRS_CPU(cpu->cpu_index), &val, len);
            hvf_set_reg(cpu, srt, val);
        }

if that works I'll cook up a proper patch.
Mads Ynddal Sept. 26, 2022, 11:20 a.m. UTC | #4
>>> On 22 Sep 2022, at 16.58, Alex Bennée <alex.bennee@linaro.org> wrote:
>>> 
>>> Now that MxTxAttrs encodes a CPU we should use that to figure it out.
>>> This solves edge cases like accessing via gdbstub or qtest.
>>> 
>>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>>> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/124
>>> 
>>> ---
>>> v2
>>> - update for new field
>>> - bool asserts
>>> ---
>>> hw/intc/arm_gic.c | 39 ++++++++++++++++++++++-----------------
>>> 1 file changed, 22 insertions(+), 17 deletions(-)
>>> 
>>> diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
>>> index 492b2421ab..b58d3c4a95 100644
>>> --- a/hw/intc/arm_gic.c
>>> +++ b/hw/intc/arm_gic.c
>>> @@ -56,17 +56,22 @@ static const uint8_t gic_id_gicv2[] = {
>>>    0x04, 0x00, 0x00, 0x00, 0x90, 0xb4, 0x2b, 0x00, 0x0d, 0xf0, 0x05, 0xb1
>>> };
>>> 
>>> -static inline int gic_get_current_cpu(GICState *s)
>>> +static inline int gic_get_current_cpu(GICState *s, MemTxAttrs attrs)
>>> {
>>> -    if (!qtest_enabled() && s->num_cpu > 1) {
>>> -        return current_cpu->cpu_index;
>>> -    }
>>> -    return 0;
>>> +    /*
>>> +     * Something other than a CPU accessing the GIC would be a bug as
>>> +     * would a CPU index higher than the GICState expects to be
>>> +     * handling
>>> +     */
>>> +    g_assert(attrs.requester_is_cpu);
>>> +    g_assert(attrs.cpu_index < s->num_cpu);
>>> +
>>> +    return attrs.requester_id;
>>> }
>> 
>> The asserts here abort on macOS, with HVF accelerator:
>> 
>> ERROR:../hw/intc/arm_gic.c:66:gic_get_current_cpu: assertion failed: (attrs.requester_is_cpu)
>> Bail out! ERROR:../hw/intc/arm_gic.c:66:gic_get_current_cpu: assertion failed: (attrs.requester_is_cpu)
>> 
>> If I revert the changes inside this function, it seemingly works
>> again.
> 
> Thanks for testing.
> 
> I guess this is because the we have a soft GIC for HVF. Somewhere in the
> hvf code path we must encode up an MemTxAttrs when the gic is accessed.
> 
> Could you try in the EC_DATAABORT path in
> target/arm/hvf/hvf.c:hvf_vcpu_exec:
> 
>        if (iswrite) {
>            val = hvf_get_reg(cpu, srt);
>            address_space_write(&address_space_memory,
>                                hvf_exit->exception.physical_address,
>                                MEMTXATTRS_CPU(cpu->cpu_index), &val, len);
>        } else {
>            address_space_read(&address_space_memory,
>                               hvf_exit->exception.physical_address,
>                               MEMTXATTRS_CPU(cpu->cpu_index), &val, len);
>            hvf_set_reg(cpu, srt, val);
>        }
> 
> if that works I'll cook up a proper patch.
> 
> -- 
> Alex Bennée

Perfect. This fixes the issue.
diff mbox series

Patch

diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
index 492b2421ab..b58d3c4a95 100644
--- a/hw/intc/arm_gic.c
+++ b/hw/intc/arm_gic.c
@@ -56,17 +56,22 @@  static const uint8_t gic_id_gicv2[] = {
     0x04, 0x00, 0x00, 0x00, 0x90, 0xb4, 0x2b, 0x00, 0x0d, 0xf0, 0x05, 0xb1
 };
 
-static inline int gic_get_current_cpu(GICState *s)
+static inline int gic_get_current_cpu(GICState *s, MemTxAttrs attrs)
 {
-    if (!qtest_enabled() && s->num_cpu > 1) {
-        return current_cpu->cpu_index;
-    }
-    return 0;
+    /*
+     * Something other than a CPU accessing the GIC would be a bug as
+     * would a CPU index higher than the GICState expects to be
+     * handling
+     */
+    g_assert(attrs.requester_is_cpu);
+    g_assert(attrs.cpu_index < s->num_cpu);
+
+    return attrs.requester_id;
 }
 
-static inline int gic_get_current_vcpu(GICState *s)
+static inline int gic_get_current_vcpu(GICState *s, MemTxAttrs attrs)
 {
-    return gic_get_current_cpu(s) + GIC_NCPU;
+    return gic_get_current_cpu(s, attrs) + GIC_NCPU;
 }
 
 /* Return true if this GIC config has interrupt groups, which is
@@ -951,7 +956,7 @@  static uint32_t gic_dist_readb(void *opaque, hwaddr offset, MemTxAttrs attrs)
     int cm;
     int mask;
 
-    cpu = gic_get_current_cpu(s);
+    cpu = gic_get_current_cpu(s, attrs);
     cm = 1 << cpu;
     if (offset < 0x100) {
         if (offset == 0) {      /* GICD_CTLR */
@@ -1182,7 +1187,7 @@  static void gic_dist_writeb(void *opaque, hwaddr offset,
     int i;
     int cpu;
 
-    cpu = gic_get_current_cpu(s);
+    cpu = gic_get_current_cpu(s, attrs);
     if (offset < 0x100) {
         if (offset == 0) {
             if (s->security_extn && !attrs.secure) {
@@ -1476,7 +1481,7 @@  static void gic_dist_writel(void *opaque, hwaddr offset,
         int mask;
         int target_cpu;
 
-        cpu = gic_get_current_cpu(s);
+        cpu = gic_get_current_cpu(s, attrs);
         irq = value & 0xf;
         switch ((value >> 24) & 3) {
         case 0:
@@ -1780,7 +1785,7 @@  static MemTxResult gic_thiscpu_read(void *opaque, hwaddr addr, uint64_t *data,
                                     unsigned size, MemTxAttrs attrs)
 {
     GICState *s = (GICState *)opaque;
-    return gic_cpu_read(s, gic_get_current_cpu(s), addr, data, attrs);
+    return gic_cpu_read(s, gic_get_current_cpu(s, attrs), addr, data, attrs);
 }
 
 static MemTxResult gic_thiscpu_write(void *opaque, hwaddr addr,
@@ -1788,7 +1793,7 @@  static MemTxResult gic_thiscpu_write(void *opaque, hwaddr addr,
                                      MemTxAttrs attrs)
 {
     GICState *s = (GICState *)opaque;
-    return gic_cpu_write(s, gic_get_current_cpu(s), addr, value, attrs);
+    return gic_cpu_write(s, gic_get_current_cpu(s, attrs), addr, value, attrs);
 }
 
 /* Wrappers to read/write the GIC CPU interface for a specific CPU.
@@ -1818,7 +1823,7 @@  static MemTxResult gic_thisvcpu_read(void *opaque, hwaddr addr, uint64_t *data,
 {
     GICState *s = (GICState *)opaque;
 
-    return gic_cpu_read(s, gic_get_current_vcpu(s), addr, data, attrs);
+    return gic_cpu_read(s, gic_get_current_vcpu(s, attrs), addr, data, attrs);
 }
 
 static MemTxResult gic_thisvcpu_write(void *opaque, hwaddr addr,
@@ -1827,7 +1832,7 @@  static MemTxResult gic_thisvcpu_write(void *opaque, hwaddr addr,
 {
     GICState *s = (GICState *)opaque;
 
-    return gic_cpu_write(s, gic_get_current_vcpu(s), addr, value, attrs);
+    return gic_cpu_write(s, gic_get_current_vcpu(s, attrs), addr, value, attrs);
 }
 
 static uint32_t gic_compute_eisr(GICState *s, int cpu, int lr_start)
@@ -1860,7 +1865,7 @@  static uint32_t gic_compute_elrsr(GICState *s, int cpu, int lr_start)
 
 static void gic_vmcr_write(GICState *s, uint32_t value, MemTxAttrs attrs)
 {
-    int vcpu = gic_get_current_vcpu(s);
+    int vcpu = gic_get_current_vcpu(s, attrs);
     uint32_t ctlr;
     uint32_t abpr;
     uint32_t bpr;
@@ -1995,7 +2000,7 @@  static MemTxResult gic_thiscpu_hyp_read(void *opaque, hwaddr addr, uint64_t *dat
 {
     GICState *s = (GICState *)opaque;
 
-    return gic_hyp_read(s, gic_get_current_cpu(s), addr, data, attrs);
+    return gic_hyp_read(s, gic_get_current_cpu(s, attrs), addr, data, attrs);
 }
 
 static MemTxResult gic_thiscpu_hyp_write(void *opaque, hwaddr addr,
@@ -2004,7 +2009,7 @@  static MemTxResult gic_thiscpu_hyp_write(void *opaque, hwaddr addr,
 {
     GICState *s = (GICState *)opaque;
 
-    return gic_hyp_write(s, gic_get_current_cpu(s), addr, value, attrs);
+    return gic_hyp_write(s, gic_get_current_cpu(s, attrs), addr, value, attrs);
 }
 
 static MemTxResult gic_do_hyp_read(void *opaque, hwaddr addr, uint64_t *data,