[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH v4 20/25] xen/riscv: create APLIC DT node for guest domains


  • To: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
  • From: Jan Beulich <jbeulich@xxxxxxxx>
  • Date: Wed, 1 Jul 2026 13:58:41 +0200
  • Authentication-results: eu.smtp.expurgate.cloud; dkim=pass header.s=google header.d=suse.com header.i="@suse.com" header.h="Content-Transfer-Encoding:In-Reply-To:Autocrypt:From:Content-Language:References:Cc:To:Subject:User-Agent:MIME-Version:Date:Message-ID"
  • Autocrypt: addr=jbeulich@xxxxxxxx; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL
  • Cc: Romain Caritey <Romain.Caritey@xxxxxxxxxxxxx>, Baptiste Le Duc <baptiste.le-duc@xxxxxxxxxx>, Alistair Francis <alistair.francis@xxxxxxx>, Connor Davis <connojdavis@xxxxxxxxx>, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Anthony PERARD <anthony.perard@xxxxxxxxxx>, Michal Orzel <michal.orzel@xxxxxxx>, Julien Grall <julien@xxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
  • Delivery-date: Wed, 01 Jul 2026 11:58:52 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 01.07.2026 13:55, Oleksii Kurochko wrote:
> On 6/29/26 5:26 PM, Jan Beulich wrote:
>> On 26.06.2026 17:46, Oleksii Kurochko wrote:
>>> --- a/xen/arch/riscv/vaplic.c
>>> +++ b/xen/arch/riscv/vaplic.c
>>> @@ -9,6 +9,8 @@
>>>    */
>>>   
>>>   #include <xen/errno.h>
>>> +#include <xen/fdt-kernel.h>
>>> +#include <xen/libfdt/libfdt.h>
>>>   #include <xen/sched.h>
>>>   #include <xen/xvmalloc.h>
>>>   
>>> @@ -19,6 +21,11 @@
>>>   
>>>   #include "aplic-priv.h"
>>>   
>>> +#define VAPLIC_COMPATIBLE "riscv,aplic"
>>> +#define VAPLIC_NUM_SOURCES 96
>>
>> So for the IMSIC the host value is relevant, but for the APLIC the count is
>> an arbitrary(?) compile time constant? Why?
> If you are referring to the number of IMSIC interrupt identities, the 
> IMSIC node has separate properties for the host and guest:
> 
> ```yaml
> riscv,num-ids:
>    $ref: /schemas/types.yaml#/definitions/uint32
>    minimum: 63
>    maximum: 2047
>    description:
>      Number of interrupt identities supported by the IMSIC interrupt file.
> 
> riscv,num-guest-ids:
>    $ref: /schemas/types.yaml#/definitions/uint32
>    minimum: 63
>    maximum: 2047
>    description:
>      Number of interrupt identities supported by the IMSIC guest 
> interrupt file. If not specified, it is assumed to be the same as the 
> value of the `riscv,num-ids` property.
> ```
> 
> Therefore, if `riscv,num-guest-ids` is not explicitly specified, the 
> predefined value `GUEST_IMSIC_NUM_IDS` is used.
> 
> No equivalent property exists for APLIC, which is why the value is 
> explicitly hardcoded here. To some extent, the chosen number is 
> arbitrary, but I used the same value that QEMU uses when creating the 
> APLIC node.
> 
> It probably makes sense to limit this value in a similar way to IMSIC, 
> at least for now, since the case where the number of VAPLIC sources 
> exceeds the number of host APLIC sources is not supported (assuming that 
> configuration is even valid). In other words, we could use:
>    min(VAPLIC_NUM_SOURCES, host_num_sources)
> 
> Would that make sense?

Perhaps, yes. Just with the constant again named appropriately for its
purpose (see comments on an earlier patch).

Jan



 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.