From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C6C976121 for ; Wed, 12 Apr 2023 14:48:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681310880; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+ZFIv/p/zrHXi9Hb3mDpf82IzUDGx965Bpax3jM97+I=; b=NKszh3qtwaXt4iIXO7Cas/6/7wGFBSRbjPx3Lrqvcft427oY5DqX3LVW3v/G2c9e1mREt8 cjSbrpCIJMEiq00ntBLn0hNgCjUCUda8tYp5IptPm5O6Om7jI8y4bK9Q2ZgXvfs1jaI1oi QWGIlmUeE03VQ9tw536coqwJsTeoFWU= Received: from mail-qk1-f200.google.com (mail-qk1-f200.google.com [209.85.222.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-267-SglHw7HQP3idhFgQT1CIDQ-1; Wed, 12 Apr 2023 10:47:59 -0400 X-MC-Unique: SglHw7HQP3idhFgQT1CIDQ-1 Received: by mail-qk1-f200.google.com with SMTP id 1-20020a370301000000b0074681bc7f42so5992843qkd.8 for ; Wed, 12 Apr 2023 07:47:59 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1681310879; x=1683902879; h=content-transfer-encoding:mime-version:message-id:date:references :in-reply-to:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Z7aoSHBk9B3SuF51OwG6nN2I/gKWPktJ/GEECG1+4VA=; b=EqriTYvGKSjzsjyCqpFseoAClrNbiix7ee20PTNMAqjZFwBEyZYno7g/EgaIjhgHH6 0IfcDSekmFJfmPWzNixDIlQb5OF9FFm2R+MW9CIoZ7clRj2L1+GzhCvXSmCsfXwKDKND xolvjdThBdA/kAE6ZSkOyxmXbgtukGzzRGPtfeDny1fqkHWFYvxVvt2/R9vi8BlPYJIg DdmHus0eIWWa436DYw+YdUJw0hXi8xUf3gqe/YhMYGCb9+qDPF3T63oIhLSsp2q7rOIq Jes8SxGLHIDKEHTp79Ll17dk5DbFhkEUFfb67jHH/3s17pv4bYdQ5ibO8LuM4ONIIISN hdxg== X-Gm-Message-State: AAQBX9eOMHCSSxVlW1HK6NIuCClPU/5PMMW5DACbBNF2Hr4AGb6aK08E VwEVKq0aTplSzGyCqWrJCTX6Aw5G5rL8MJrZiFWvLZrEjoM5Qy+YMAdUPUOXVmcro6b4sWawrLh o6p1uUsgI0ojlsJfq10L1mQ67g1TVbqiSFHnefHEMJSc/v2YIB4/+sR6yV3L1ypY6GIYAHFdOPU ZK5g== X-Received: by 2002:a05:622a:1cb:b0:3e3:824f:45f1 with SMTP id t11-20020a05622a01cb00b003e3824f45f1mr3961277qtw.27.1681310879078; Wed, 12 Apr 2023 07:47:59 -0700 (PDT) X-Google-Smtp-Source: AKy350aG1bLmg0WEoDAicV85azZn9oNrATuG6ivlTsH69LgN751j4sEUZ7khp0xPnzerYNinK4cpLA== X-Received: by 2002:a05:622a:1cb:b0:3e3:824f:45f1 with SMTP id t11-20020a05622a01cb00b003e3824f45f1mr3961249qtw.27.1681310878775; Wed, 12 Apr 2023 07:47:58 -0700 (PDT) Received: from fedora (g2.ign.cz. [91.219.240.8]) by smtp.gmail.com with ESMTPSA id d9-20020ac86689000000b003e3910db4f1sm4310584qtp.35.2023.04.12.07.47.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Apr 2023 07:47:58 -0700 (PDT) From: Vitaly Kuznetsov To: Paolo Bonzini , Sean Christopherson Cc: Greg Kroah-Hartman , Jeremi Piotrowski , patches@lists.linux.dev Subject: Re: [PATCH 6.2 101/173] KVM: SVM: Flush Hyper-V TLB when required In-Reply-To: References: <20230412082838.125271466@linuxfoundation.org> <20230412082842.164450040@linuxfoundation.org> <87jzyhfnza.fsf@redhat.com> Date: Wed, 12 Apr 2023 16:47:55 +0200 Message-ID: <87edopf97o.fsf@redhat.com> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Paolo Bonzini writes: > On Wed, Apr 12, 2023 at 4:26=E2=80=AFPM Sean Christopherson wrote: >> There are no functional issues with the fix, and there's no evidence tha= t KVM is >> to blame for the slow L2 boot times when the TDP MMU is enabled. >> >> > Jeremi, Sean, do you thing it's still worth it to push this to stable@= ? >> > IMO a small patch disabling TDP MMU on Hyper-V would be better for the >> > time being... >> >> Yes, I think it's worth pushing to stable. The fix is valid even if we = end up >> disabling the TDP MMU on Hyper-V as a workaround. And the fix is mandat= ory if/when >> the TDP MMU is re-enabled, or if we root cause the boot problem sooner t= han later >> and don't have to resort to disabling the TDP MMU. > > Agreed plus it's a good idea to keep this patch anyway for correctness > of kvm-amd.ko. Performance is a separate issue. OK, makes sense, without the correctness there's no point in discussing performance. --=20 Vitaly