Re: [Xen-devel] [PATCH v9 05/28] ARM: GICv3: forward pending LPIs to guests

[Andre Przywara <andre.przywara@xxxxxxx>]

Hi,

On 22/05/17 23:03, Stefano Stabellini wrote:
> On Thu, 11 May 2017, Andre Przywara wrote:
>> Upon receiving an LPI on the host, we need to find the right VCPU and
>> virtual IRQ number to get this IRQ injected.
>> Iterate our two-level LPI table to find this information quickly when
>> the host takes an LPI. Call the existing injection function to let the
>> GIC emulation deal with this interrupt.
>> Also we enhance struct pending_irq to cache the pending bit and the
>> priority information for LPIs.
> 
> I can see that you added "uint8_t lpi_priority" to pending_irq. Where
> are we caching the pending bit?

Ah, that statement is a leftover from v5, where I introduced
GIC_IRQ_GUEST_LPI_PENDING. However we don't need an explicit pending
state at the moment (the VGIC rework will probably change this), so we
get away without that bit. Will drop those words.

> Also, I don't think the priority changes need to be part of this patch;
> without out I would give my reviewed-by.

OK, will split it.

Cheers,
Andre.

> 
>> Reading the information from there is
>> faster than accessing the property table from guest memory. Also it
>> use some padding area, so does not require more memory.
>> This introduces a do_LPI() as a hardware gic_ops and a function to
>> retrieve the (cached) priority value of an LPI and a vgic_ops.
>>
>> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
>> ---
>>  xen/arch/arm/gic-v2.c            |  7 ++++
>>  xen/arch/arm/gic-v3-lpi.c        | 71 
>> ++++++++++++++++++++++++++++++++++++++++
>>  xen/arch/arm/gic-v3.c            |  1 +
>>  xen/arch/arm/gic.c               |  8 ++++-
>>  xen/arch/arm/vgic-v2.c           |  7 ++++
>>  xen/arch/arm/vgic-v3.c           | 18 ++++++++++
>>  xen/arch/arm/vgic.c              |  7 +++-
>>  xen/include/asm-arm/domain.h     |  3 +-
>>  xen/include/asm-arm/gic.h        |  2 ++
>>  xen/include/asm-arm/gic_v3_its.h |  8 +++++
>>  xen/include/asm-arm/vgic.h       |  2 ++
>>  11 files changed, 131 insertions(+), 3 deletions(-)
>>

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