On 2025-04-21 15:58:36 [+0530], Shrikanth Hegde wrote:
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 19f4d298d..123539642 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -80,8 +80,8 @@
> #include <asm/ultravisor.h>
> #include <asm/dtl.h>
> #include <asm/plpar_wrappers.h>
> -
> #include <trace/events/ipi.h>
> +#include <linux/entry-kvm.h>
>
> #include "book3s.h"
> #include "book3s_hv.h"
> @@ -4901,7 +4901,7 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64
> time_limit,
> }
>
> if (need_resched())
> - cond_resched();
> + schedule();
This looks unrelated and odd. I don't why but this should be a
cond_resched() so it can be optimized away on PREEMPT kernels.
> kvmppc_update_vpas(vcpu);
>
> @@ -5097,10 +5097,11 @@ static int kvmppc_vcpu_run_hv(struct kvm_vcpu *vcpu)
> return -EINVAL;
> }
>
> - /* No need to go into the guest when all we'll do is come back out */
> - if (signal_pending(current)) {
> - run->exit_reason = KVM_EXIT_INTR;
> - return -EINTR;
> + /* use generic frameworks to handle signals, need_resched */
> + if (__xfer_to_guest_mode_work_pending()) {
> + r = xfer_to_guest_mode_handle_work(vcpu);
This could be unconditional.
> + if (r)
> + return r;
> }
>
> #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index 153587741..4ff334532 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -34,6 +34,7 @@
> #endif
> #include <asm/ultravisor.h>
> #include <asm/setup.h>
> +#include <linux/entry-kvm.h>
>
> #include "timing.h"
> #include "../mm/mmu_decl.h"
> @@ -80,24 +81,17 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu)
> {
> int r;
>
> + /* use generic framework to handle need resched and signals */
> + if (__xfer_to_guest_mode_work_pending()) {
> + r = xfer_to_guest_mode_handle_work(vcpu);
there is nothing special you do checking and handling the work. Couldn't
you invoke xfer_to_guest_mode_handle_work() unconditionally?
> + if (r)
> + return r;
> + }
> +
> WARN_ON(irqs_disabled());
> hard_irq_disable();
>
> while (true) {
> - if (need_resched()) {
> - local_irq_enable();
> - cond_resched();
> - hard_irq_disable();
> - continue;
> - }
> -
> - if (signal_pending(current)) {
> - kvmppc_account_exit(vcpu, SIGNAL_EXITS);
> - vcpu->run->exit_reason = KVM_EXIT_INTR;
> - r = -EINTR;
> - break;
I don't how this works but couldn't SIGNAL_EXITS vanish now that it
isn't updated anymore? The stat itself moves in kvm_handle_signal_exit()
to a different counter so it is not lost. The reader just needs to look
somewhere else for it.
> - }
> -
> vcpu->mode = IN_GUEST_MODE;
>
> /*
Sebastian
