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[34.125.139.61]) by smtp.gmail.com with ESMTPSA id m2-20020a170902db0200b001dcf91da5c8sm9398420plx.95.2024.03.06.16.53.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Mar 2024 16:53:45 -0800 (PST) Date: Wed, 6 Mar 2024 16:53:41 -0800 From: David Matlack To: isaku.yamahata@intel.com Cc: kvm@vger.kernel.org, isaku.yamahata@gmail.com, linux-kernel@vger.kernel.org, Sean Christopherson , Paolo Bonzini , Michael Roth , Federico Parola Subject: Re: [RFC PATCH 0/8] KVM: Prepopulate guest memory API Message-ID: References: Precedence: bulk X-Mailing-List: kvm@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 2024-03-01 09:28 AM, isaku.yamahata@intel.com wrote: > From: Isaku Yamahata > > Implementation: > - x86 KVM MMU > In x86 KVM MMU, I chose to use kvm_mmu_do_page_fault(). It's not confined to > KVM TDP MMU. We can restrict it to KVM TDP MMU and introduce an optimized > version. Restricting to TDP MMU seems like a good idea. But I'm not quite sure how to reliably do that from a vCPU context. Checking for TDP being enabled is easy, but what if the vCPU is in guest-mode? Perhaps we can just return an error out to userspace if the vCPU is in guest-mode or TDP is disabled, and make it userspace's problem to do memory mapping before loading any vCPU state.