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Date: Mon, 25 Aug 2025 22:26:38 +0000
From: Wei Liu <wei.liu@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Sean Christopherson <seanjc@google.com>, Marc Zyngier <maz@kernel.org>,
	Oliver Upton <oliver.upton@linux.dev>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Tianrui Zhao <zhaotianrui@loongson.cn>,
	Bibo Mao <maobibo@loongson.cn>, Huacai Chen <chenhuacai@kernel.org>,
	Anup Patel <anup@brainfault.org>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
	Andy Lutomirski <luto@kernel.org>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Frederic Weisbecker <frederic@kernel.org>,
	Neeraj Upadhyay <neeraj.upadhyay@kernel.org>,
	Joel Fernandes <joelagnelf@nvidia.com>,
	Josh Triplett <josh@joshtriplett.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	Uladzislau Rezki <urezki@gmail.com>, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
	kvm@vger.kernel.org, loongarch@lists.linux.dev,
	kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
	linux-hyperv@vger.kernel.org, rcu@vger.kernel.org
Subject: Re: [PATCH 0/5] Drivers: hv: Fix NEED_RESCHED_LAZY and use common
 APIs
Message-ID: <aKzjHjtI2fbFjBpe@liuwe-devbox-ubuntu-v2.tail21d00.ts.net>
References: <20250825200622.3759571-1-seanjc@google.com>
 <20250825222319.GO3419281@noisy.programming.kicks-ass.net>
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In-Reply-To: <20250825222319.GO3419281@noisy.programming.kicks-ass.net>

On Tue, Aug 26, 2025 at 12:23:19AM +0200, Peter Zijlstra wrote:
> On Mon, Aug 25, 2025 at 01:06:17PM -0700, Sean Christopherson wrote:
> > Fix a bug where MSHV root partitions don't honor NEED_RESCHED_LAZY, and then
> > deduplicate the TIF related MSHV code by turning the "kvm" entry APIs into
> > more generic "virt" APIs (which ideally would have been done when MSHV root
> > support was added).
> > 
> > Assuming all is well, maybe this could go through the tip tree?
> > 
> > The Hyper-V stuff and non-x86 architectures are compile-tested only.
> 
> I suspect there's more of this wreckage in the new VTL driver that
> they just put in:
> 
>   https://lore.kernel.org/all/20250729051436.190703-3-namjain@linux.microsoft.com/
> 
> although ideally they rip that thing out. I don't know how that code can
> ever be correct.

Please give us some time, Peter. I have asked the corresponding team to
respond to your comments.

Wei