On Thu, Sep 19, 2019 at 8:09 AM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> Entering a guest is similar to exiting to user space. Pending work like
> handling signals, rescheduling, task work etc. needs to be handled before
> that.
>
> Provide generic infrastructure to avoid duplication of the same handling code
> all over the place.
>
> Update ARM64 struct kvm_vcpu_stat with a signal_exit member so the generic
> code compiles.
>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> ---
> arch/arm64/include/asm/kvm_host.h | 1
> include/linux/entry-common.h | 66 ++++++++++++++++++++++++++++++++++++++
> kernel/entry/common.c | 44 +++++++++++++++++++++++++
> 3 files changed, 111 insertions(+)
>
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -409,6 +409,7 @@ struct kvm_vcpu_stat {
> u64 wfi_exit_stat;
> u64 mmio_exit_user;
> u64 mmio_exit_kernel;
> + u64 signal_exits;
> u64 exits;
> };
>
> --- a/include/linux/entry-common.h
> +++ b/include/linux/entry-common.h
> @@ -255,4 +255,70 @@ static inline void arch_syscall_exit_tra
> /* Common syscall exit function */
> void syscall_exit_to_usermode(struct pt_regs *regs, long syscall, long retval);
>
> +#if IS_ENABLED(CONFIG_KVM)
> +
> +#include <linux/kvm_host.h>
> +
> +#ifndef ARCH_EXIT_TO_GUESTMODE_WORK
> +# define ARCH_EXIT_TO_GUESTMODE_WORK (0)
> +#endif
> +
> +#define EXIT_TO_GUESTMODE_WORK \
> + (_TIF_NEED_RESCHED | _TIF_SIGPENDING | _TIF_NOTIFY_RESUME | \
> + ARCH_EXIT_TO_GUESTMODE_WORK)
> +
> +int core_exit_to_guestmode_work(struct kvm *kvm, struct kvm_vcpu *vcpu,
> + unsigned long ti_work);
> +
> +/**
> + * arch_exit_to_guestmode - Architecture specific exit to guest mode function
> + * @kvm: Pointer to the guest instance
> + * @vcpu: Pointer to current's VCPU data
> + * @ti_work: Cached TIF flags gathered in exit_to_guestmode()
> + *
> + * Invoked from core_exit_to_guestmode_work(). Can be replaced by
> + * architecture specific code.
> + */
> +static inline int arch_exit_to_guestmode(struct kvm *kvm, struct kvm_vcpu *vcpu,
> + unsigned long ti_work);
Can you add a comment about whether IRQs are supposed to be off (I
assume they are) and perhaps a lockdep assertion to verify it?
