Re: [PATCH v3 1/2] target/arm: Support SError injection

[Marc Zyngier <maz@kernel.org>]

Hi Gavin,

On 2020-02-14 05:59, Gavin Shan wrote:
> This supports SError injection, which will be used by "virt" board to
> simulating the behavior of NMI injection in next patch. As Peter 
> Maydell
> suggested, this adds a new interrupt (ARM_CPU_SERROR), which is 
> parallel
> to CPU_INTERRUPT_HARD. The backend depends on if kvm is enabled or not.
> kvm_vcpu_ioctl(cpu, KVM_SET_VCPU_EVENTS) is leveraged to inject SError
> or data abort to guest. When TCG is enabled, the behavior is simulated
> by injecting SError and data abort to guest.
> 
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
>  target/arm/cpu.c      | 69 +++++++++++++++++++++++++++++++++++--------
>  target/arm/cpu.h      | 17 ++++++-----
>  target/arm/helper.c   |  6 ++++
>  target/arm/m_helper.c |  8 +++++
>  4 files changed, 81 insertions(+), 19 deletions(-)
> 

[...]

> @@ -656,7 +682,8 @@ static void arm_cpu_set_irq(void *opaque, int irq,
> int level)
>          [ARM_CPU_IRQ] = CPU_INTERRUPT_HARD,
>          [ARM_CPU_FIQ] = CPU_INTERRUPT_FIQ,
>          [ARM_CPU_VIRQ] = CPU_INTERRUPT_VIRQ,
> -        [ARM_CPU_VFIQ] = CPU_INTERRUPT_VFIQ
> +        [ARM_CPU_VFIQ] = CPU_INTERRUPT_VFIQ,
> +        [ARM_CPU_SERROR] = CPU_INTERRUPT_SERROR,

I'm a bit concerned with this. It makes sense for a host, but doesn't
allow the SError signal to be virtualised (there should be a VSError
signal in this list that can be injected via HCR_EL2.VA, just like
VIRQ is injected by HCR_EL2.VI).

Given that people use QEMU as a development platform for hypervisors,
I'd really like this functionality to be supported from day-1.

There is also the whole RAS stuff which quite a lot of work, but let's
start at least with the full ARMv8.0 semantics.

Thanks,

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