Re: [PATCH v24 09/10] target-arm: kvm64: handle SIGBUS signal from kernel or KVM

[Peter Maydell <peter.maydell@linaro.org>]

On Mon, 17 Feb 2020 at 13:10, Dongjiu Geng <gengdongjiu@huawei.com> wrote:
>
> Add a SIGBUS signal handler. In this handler, it checks the SIGBUS type,
> translates the host VA delivered by host to guest PA, then fills this PA
> to guest APEI GHES memory, then notifies guest according to the SIGBUS
> type.
>
> When guest accesses the poisoned memory, it will generate a Synchronous
> External Abort(SEA). Then host kernel gets an APEI notification and calls
> memory_failure() to unmapped the affected page in stage 2, finally
> returns to guest.
>
> Guest continues to access the PG_hwpoison page, it will trap to KVM as
> stage2 fault, then a SIGBUS_MCEERR_AR synchronous signal is delivered to
> Qemu, Qemu records this error address into guest APEI GHES memory and
> notifes guest using Synchronous-External-Abort(SEA).
>
> In order to inject a vSEA, we introduce the kvm_inject_arm_sea() function
> in which we can setup the type of exception and the syndrome information.
> When switching to guest, the target vcpu will jump to the synchronous
> external abort vector table entry.
>
> The ESR_ELx.DFSC is set to synchronous external abort(0x10), and the
> ESR_ELx.FnV is set to not valid(0x1), which will tell guest that FAR is
> not valid and hold an UNKNOWN value. These values will be set to KVM
> register structures through KVM_SET_ONE_REG IOCTL.
>
> Signed-off-by: Dongjiu Geng <gengdongjiu@huawei.com>
> Signed-off-by: Xiang Zheng <zhengxiang9@huawei.com>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> Acked-by: Xiang Zheng <zhengxiang9@huawei.com>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM