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[34.168.104.7]) by smtp.gmail.com with ESMTPSA id u8-20020a1709026e0800b0018863e1bd3csm159522plk.134.2022.11.04.13.27.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Nov 2022 13:27:18 -0700 (PDT) Date: Fri, 4 Nov 2022 20:27:14 +0000 From: Sean Christopherson To: Isaku Yamahata Subject: Re: [PATCH 00/44] KVM: Rework kvm_init() and hardware enabling Message-ID: References: <20221102231911.3107438-1-seanjc@google.com> <20221104071749.GC1063309@ls.amr.corp.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221104071749.GC1063309@ls.amr.corp.intel.com> Cc: Matthew Rosato , David Hildenbrand , Yuan Yao , Paul Walmsley , linux-kernel@vger.kernel.org, Michael Ellerman , linux-riscv@lists.infradead.org, Claudio Imbrenda , kvmarm@lists.cs.columbia.edu, linux-s390@vger.kernel.org, Janosch Frank , Marc Zyngier , Huacai Chen , Aleksandar Markovic , Christian Borntraeger , Chao Gao , Eric Farman , Albert Ou , kvm@vger.kernel.org, Atish Patra , kvmarm@lists.linux.dev, Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Isaku Yamahata , Fabiano Rosas , linux-mips@vger.kernel.org, Palmer Dabbelt , kvm-riscv@lists.infradead.org, Paolo Bonzini , Vitaly Kuznetsov , linuxppc-dev@lists.ozlabs.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Fri, Nov 04, 2022, Isaku Yamahata wrote: > Thanks for the patch series. I the rebased TDX KVM patch series and it worked. > Since cpu offline needs to be rejected in some cases(To keep at least one cpu > on a package), arch hook for cpu offline is needed. I hate to bring this up because I doubt there's a real use case for SUSPEND with TDX, but the CPU offline path isn't just for true offlining of CPUs. When the system enters SUSPEND, only the initiating CPU goes through kvm_suspend()+kvm_resume(), all responding CPUs go through CPU offline+online. I.e. disallowing all CPUs from going "offline" will prevent suspending the system. I don't see anything in the TDX series or the specs that suggests suspend+resume is disallowed when TDX is enabled, so blocking that seems just as wrong as preventing software from soft-offlining CPUs. _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f178.google.com (mail-pf1-f178.google.com [209.85.210.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CD784AD25 for ; Fri, 4 Nov 2022 20:27:19 +0000 (UTC) Received: by mail-pf1-f178.google.com with SMTP id g62so5445070pfb.10 for ; Fri, 04 Nov 2022 13:27:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=TzyhTv3BAtgpGpRr8HnNLx/d2zCvSqkboAFtik4Imo0=; b=q/PTXKQj3ArVm2XzZe97QeFygVMm1eXh+9AVtXcJ75aOhS7rpOmmmorCukrcxmTsXJ xtHpP7JyICLKwJpO4UdyBCOfADg9j8qWzQtBsGyOUBj4dtUE2hEcaa0M2lJNL2RYHNdm t9CE40syL4mSgI+9axRmHRY3m49U53Bcc5xsUL4w5HmCnvq3rZFCi8RspoeZ0S4Nhg0P dklWYN0e+iqclhNFPVLNqLlrIm4bRgIuUSiy6nVFx0aKBZbtXqUzzmm+oTu43A9TiINS r9mhyi03/1kAIfHUOzdEnLew/bMGSFKH13ZsSBoEdZkxO+PvUKRhjXGV6DaJ6ZELthJK tWVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=TzyhTv3BAtgpGpRr8HnNLx/d2zCvSqkboAFtik4Imo0=; b=q7g3r96Kky2zG9K/TJ7L+KX6aUHYjrP/px3mlPlcXwGwSj9cntDT3Ys5BllPkFXejj 6Tv84RHRW6sis7oRQOwzs4PB0flMFkyZLzKLGBhoswlotCBqLVlx/mfOtrFf+J5Q+AzW TyT2EtPSqvBi+R1POnZjozfxpvu1auqTL6mj8+Ox8KBeCiZmmSWeCqTR/kMsFQaXSHIb GuQrJIZrEi+NNWa092EHQLQIQUIxByWsXNAv6KP8xs9PSx6Gahl4b5bCj8/WnwtWy1MO /vcUNvL0JsY+uoV36UQ3Vxf2eENDvnUSDb6029gkP4JDt32z+svlid/DsKiyX+uMOgt2 1xTw== X-Gm-Message-State: ACrzQf3ig8bLyczs/DzJVqB4Zi/f6gd8TwuzOJGCHyzAk+GXivzylUzc EwJIDdPdTI2E1tH1AQtwNFiplg== X-Google-Smtp-Source: AMsMyM6nILnCIcSIsk5JMrE+WRVnxFnaYDn7QGx3yWf1KAa3dZc7TNSn3aZcg19Xay3NbhiF32a9mw== X-Received: by 2002:a05:6a00:1781:b0:561:7f7f:dc38 with SMTP id s1-20020a056a00178100b005617f7fdc38mr38037687pfg.42.1667593638927; Fri, 04 Nov 2022 13:27:18 -0700 (PDT) Received: from google.com (7.104.168.34.bc.googleusercontent.com. [34.168.104.7]) by smtp.gmail.com with ESMTPSA id u8-20020a1709026e0800b0018863e1bd3csm159522plk.134.2022.11.04.13.27.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Nov 2022 13:27:18 -0700 (PDT) Date: Fri, 4 Nov 2022 20:27:14 +0000 From: Sean Christopherson To: Isaku Yamahata Cc: Paolo Bonzini , Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Matthew Rosato , Eric Farman , Vitaly Kuznetsov , James Morse , Alexandru Elisei , Suzuki K Poulose , Oliver Upton , Atish Patra , David Hildenbrand , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, Isaku Yamahata , Fabiano Rosas , Michael Ellerman , Chao Gao , Thomas Gleixner , Yuan Yao Subject: Re: [PATCH 00/44] KVM: Rework kvm_init() and hardware enabling Message-ID: References: <20221102231911.3107438-1-seanjc@google.com> <20221104071749.GC1063309@ls.amr.corp.intel.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221104071749.GC1063309@ls.amr.corp.intel.com> Message-ID: <20221104202714.rP4EMA-sjFE_Fhn8It4rRy5PD6fzb_Bdf54Sljnb2jM@z> On Fri, Nov 04, 2022, Isaku Yamahata wrote: > Thanks for the patch series. I the rebased TDX KVM patch series and it worked. > Since cpu offline needs to be rejected in some cases(To keep at least one cpu > on a package), arch hook for cpu offline is needed. I hate to bring this up because I doubt there's a real use case for SUSPEND with TDX, but the CPU offline path isn't just for true offlining of CPUs. When the system enters SUSPEND, only the initiating CPU goes through kvm_suspend()+kvm_resume(), all responding CPUs go through CPU offline+online. I.e. disallowing all CPUs from going "offline" will prevent suspending the system. I don't see anything in the TDX series or the specs that suggests suspend+resume is disallowed when TDX is enabled, so blocking that seems just as wrong as preventing software from soft-offlining CPUs.