From: Marc Zyngier <maz@kernel.org>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org,
Nicholas Piggin <npiggin@gmail.com>,
kvm-riscv@lists.infradead.org,
Paolo Bonzini <pbonzini@redhat.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH kernel v2] KVM: PPC: Make KVM_CAP_IRQFD_RESAMPLE support platform dependent
Date: Tue, 20 Sep 2022 17:08:13 +0100 [thread overview]
Message-ID: <874jx2kp02.wl-maz@kernel.org> (raw)
In-Reply-To: <20220920125143.28009-1-aik@ozlabs.ru>
On Tue, 20 Sep 2022 13:51:43 +0100,
Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
>
> When introduced, IRQFD resampling worked on POWER8 with XICS. However
> KVM on POWER9 has never implemented it - the compatibility mode code
> ("XICS-on-XIVE") misses the kvm_notify_acked_irq() call and the native
> XIVE mode does not handle INTx in KVM at all.
>
> This moved the capability support advertising to platforms and stops
> advertising it on XIVE, i.e. POWER9 and later.
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> Acked-by: Nicholas Piggin <npiggin@gmail.com>
> [For KVM RISC-V]
> Acked-by: Anup Patel <anup@brainfault.org>
> ---
> Changes:
> v2:
> * removed ifdef for ARM64.
The same argument applies to both x86 and s390, which do select
HAVE_KVM_IRQFD from the KVM config option. Only power allows this
option to be selected depending on the underlying interrupt controller
emulation.
As for riscv and mips, they don't select HAVE_KVM_IRQFD, and this
isn't a user-selectable option. So why do they get patched at all?
My conclusion is that:
- only power needs the #ifdefery in the arch-specific code
- arm64, s390 and x86 can use KVM_CAP_IRQFD_RESAMPLE without a #ifdef
- mips and riscv should be left alone
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
next prev parent reply other threads:[~2022-09-20 16:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-20 12:51 [PATCH kernel v2] KVM: PPC: Make KVM_CAP_IRQFD_RESAMPLE support platform dependent Alexey Kardashevskiy
2022-09-20 16:08 ` Marc Zyngier [this message]
2022-09-20 21:46 ` Alexey Kardashevskiy
2022-09-21 17:04 ` Marc Zyngier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=874jx2kp02.wl-maz@kernel.org \
--to=maz@kernel.org \
--cc=aik@ozlabs.ru \
--cc=kvm-ppc@vger.kernel.org \
--cc=kvm-riscv@lists.infradead.org \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=npiggin@gmail.com \
--cc=pbonzini@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).