| Message ID | 20221108115543.1425199-1-apatel@ventanamicro.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | RISC-V: KVM: Exit run-loop immediately if xfer_to_guest fails | expand |
On Nov 08 2022, Anup Patel wrote: > If xfer_to_guest_mode_handle_work() fails in the run-loop then exit > the run-loop immediately instead of doing it after some more work. > > Signed-off-by: Anup Patel <apatel@ventanamicro.com> > Reviewed-by: Andrew Jones <ajones@ventanamicro.com> > --- > arch/riscv/kvm/vcpu.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c > index 71ebbc4821f0..17d5b3f8c2ee 100644 > --- a/arch/riscv/kvm/vcpu.c > +++ b/arch/riscv/kvm/vcpu.c > @@ -984,8 +984,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) > while (ret > 0) { > /* Check conditions before entering the guest */ > ret = xfer_to_guest_mode_handle_work(vcpu); > - if (!ret) > - ret = 1; > + if (ret) > + continue; If that is supposed to exit the loop, it would be clearer to just use break. > + ret = 1; There is a condition on ret <= 0 later in the loop that no longer can be true.
On Tue, Nov 8, 2022 at 5:48 PM Andreas Schwab <schwab@suse.de> wrote: > > On Nov 08 2022, Anup Patel wrote: > > > If xfer_to_guest_mode_handle_work() fails in the run-loop then exit > > the run-loop immediately instead of doing it after some more work. > > > > Signed-off-by: Anup Patel <apatel@ventanamicro.com> > > Reviewed-by: Andrew Jones <ajones@ventanamicro.com> > > --- > > arch/riscv/kvm/vcpu.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c > > index 71ebbc4821f0..17d5b3f8c2ee 100644 > > --- a/arch/riscv/kvm/vcpu.c > > +++ b/arch/riscv/kvm/vcpu.c > > @@ -984,8 +984,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) > > while (ret > 0) { > > /* Check conditions before entering the guest */ > > ret = xfer_to_guest_mode_handle_work(vcpu); > > - if (!ret) > > - ret = 1; > > + if (ret) > > + continue; > > If that is supposed to exit the loop, it would be clearer to just use > break. This is a convention within the run-loop that we continue whenever whenever "ret" is no longer suitable to continue. I don't see any particular advantage in breaking this convention over here. > > > + ret = 1; > > There is a condition on ret <= 0 later in the loop that no longer can be > true. Yes, for now the "ret <= 0" check is useless and the compiler will optimize this comparison. We will be soon having more stuff added to run-loop (such as AIA update) which will make "ret <= 0" check useful again. > > -- > Andreas Schwab, SUSE Labs, schwab@suse.de > GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7 > "And now for something completely different." Queued this patch for Linux-6.2 Thanks, Anup
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 71ebbc4821f0..17d5b3f8c2ee 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -984,8 +984,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) while (ret > 0) { /* Check conditions before entering the guest */ ret = xfer_to_guest_mode_handle_work(vcpu); - if (!ret) - ret = 1; + if (ret) + continue; + ret = 1; kvm_riscv_gstage_vmid_update(vcpu);