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[34.140.183.197]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48dfd503a0dsm23717496f8f.47.2026.10.19.05.42.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Oct 2026 05:42:20 -0700 (PDT) Date: Mon, 19 Oct 2026 13:42:17 +0100 From: Vincent Donnefort To: Fuad Tabba Cc: Marc Zyngier , Oliver Upton , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Mark Rutland , Quentin Perret , Fuad Tabba , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] KVM: arm64: Ensure TLBs and I-cache are private to each vCPU in pKVM Message-ID: References: <20261014125510.2928306-1-fuad.tabba@linux.dev> <20261014125510.2928306-3-fuad.tabba@linux.dev> <20261019114357.3528498-1-fuad.tabba@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Oct 19, 2026 at 01:39:01PM +0100, Vincent Donnefort wrote: > On Mon, Oct 19, 2026 at 12:43:57PM +0100, Fuad Tabba wrote: > > Hi Vincent, > > > > On Mon, 19 Oct 2026 11:00:15 +0100, Vincent Donnefort wrote: > > [...] > > > > diff --git a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h > > [...] > > > > @@ -54,6 +54,9 @@ struct pkvm_hyp_vm { > > > > unsigned short refcount; > > > > hyp_spinlock_t lock; > > > > > > > > + /* Per physical CPU, the vcpu_idx of the last vCPU of this VM loaded there. */ > > > > + int *last_vcpu_ran; > > > > > > Unlikely to be a problem in pratice, but vcpu_idx is "unsigned int". I wonder if > > > this shouldn't be unsigned int here too and initialised to UINT_MAX? > > > > I'd copied int and -1 from the host's mmu->last_vcpu_ran, but the > > vcpu_idx it's comparing against here is unsigned int, so I'll switch to > > unsigned int and UINT_MAX in v2. > > > > Thanks, > > /fuad > > Also, > > as it is always allocated when pkvm_hyp_vm is, Would it make sense to add this > to pkvm_get_hyp_vm_size() instead of allocating separately? > > -- > Vincent Ha, I just saw your answer to Marc and you will switch to a per-cpu approach anyway it seems? -- Vincent