From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (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 EDE8D3CBE70 for ; Fri, 1 May 2026 14:38:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777646336; cv=none; b=gIeoy9wLMFo8w4NXUUQAsG8d2o5Dx1vmrJdPlA6Ej3YMXxnw3KGW07z7OIs8SHCftl6AU6Yw9MQ6MCyC/E5MqgLYeo+S++JB7vZ6paUtBCAfvhsuYdH/Y2qT6JWzhh2BsmzZOApUk/N7ygePnN6HzVCvokBFIg8Re8cjxIQLYpQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777646336; c=relaxed/simple; bh=Z+IuMEI+mjsG+X87wysF0aQRS0jmq1mcpBw4B+9Pbd4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=YtHA3qcvqz6ZH4qZmTuSbvDQwfkbc/hTaAw7tKfJQ8yja+jB1dPxaq/igr5NHpyet7yKCcRRKzRcHZ39jzLKoJyRNntbzLve+TG1yRSF8vh8brDHgiEduA+USqhYr+XwucDOib1ZenrNbYiJR1vUuw4NOg4w4fx6ncDs80boBic= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=dQao9CrP; arc=none smtp.client-ip=209.85.210.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="dQao9CrP" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-82f6b0a7164so2732703b3a.0 for ; Fri, 01 May 2026 07:38:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1777646334; x=1778251134; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:from:to:cc:subject:date:message-id :reply-to; bh=uk8uEZa0eDL7AYTDA5NuGODhsEPf2eVrq3K/VEvlvkQ=; b=dQao9CrPTrIShMH1HhRcC6Uk6SXMMkEK1Iys29xQU/PVuiXln7LtFusTjOxD/qGJ9q hY9OBohOJ5P047EOrr1juQFK3QUFd1yDVOY9h1h0vftq0XFfJvOXbrT2HySeLZ7zoUIo 0CpBdjLjmCZWZIBJEA1EnVtbVdNxzVukS7uzYFyvdPEGGPgXAbusNn+BhMP0WE2n5pG3 qviBm7c7rUM4MXVZWG2fDzSbFBPFP6XVoq6i4ReFPfKxXKC+0vspr4ZX6LqPPheAcDIq hefYc9rz2Jb01w2iqsH6nAaiH5SqK6AZmoRFV1h+C6BfPXFHHLd7xB9SbjsnoclzBdT3 qCxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777646334; x=1778251134; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=uk8uEZa0eDL7AYTDA5NuGODhsEPf2eVrq3K/VEvlvkQ=; b=gV1fob2eNTv4HJUdbOXlWQV842nM6VkAuFwgAVj6JdRlXkln09LK/ZC9v00TK6diD3 6sqFcoWO4F6+euAZnLO2hgMIVuz8uFt9OX51i1i6RnlW6JP6zih0x7XYg9Jt4hEf5aHA dtjlaWRup3OHgxBC3bvVwCiFEs1u+2vmO+U6hO1pO0MDwmz1hArMLfI7IKfwloq85HmL jjdQw4psma+0iqWqc6JlEHgh6HPQuYCG3KKeC8/9IOK40CTvYk56oxdg0cwZLYAct2k/ xoOH/AQRNIvc4mV6/lzDD20o+JyqyIPgurPguLSRL7XAQOBSPKppdlZWsh5Cru0Jb5kr vWGQ== X-Gm-Message-State: AOJu0YwVUr0A8W+81KkOS1vFNJn5pIp8dLbMOOZdrADi7a8Ll5e2e/TY rVYD0Gy6tSbofybkgSqzNCyvd+3M1SrpOU+2VVHs816GpKkQ/q0UXgH5QzFtljofla5grgMFRM4 l36rK4A== X-Received: from pfmy21.prod.google.com ([2002:aa7:8055:0:b0:82f:7ce1:182]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:2d9a:b0:82f:aae5:c795 with SMTP id d2e1a72fcca58-834fdc9aa92mr9170785b3a.48.1777646334099; Fri, 01 May 2026 07:38:54 -0700 (PDT) Date: Fri, 1 May 2026 07:38:52 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260430150747.76749-1-pbonzini@redhat.com> <20260430150747.76749-27-pbonzini@redhat.com> Message-ID: Subject: Re: [PATCH 26/28] KVM: SVM: enable GMET and set it in MMU role From: Sean Christopherson To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, d.riley@proxmox.com, jon@nutanix.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Fri, May 01, 2026, Paolo Bonzini wrote: > On Thu, Apr 30, 2026 at 9:15=E2=80=AFPM Sean Christopherson wrote: > > > > On Thu, Apr 30, 2026, Paolo Bonzini wrote: > > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > > > index e7fdd7a9c280..3895d8794366 100644 > > > --- a/arch/x86/kvm/svm/svm.c > > > +++ b/arch/x86/kvm/svm/svm.c > > > @@ -138,6 +138,9 @@ module_param(pause_filter_count_max, ushort, 0444= ); > > > bool __ro_after_init npt_enabled =3D true; > > > module_param_named(npt, npt_enabled, bool, 0444); > > > > > > +bool gmet_enabled =3D true; > > > > This really should be hardcoded false, with no module param, until "ena= ble GMET > > for guests". Otherwise stopping here means KVM is over-reporting suppo= rt. >=20 > Are module parameters reporting support of nested features? Not strictly speaking, no. But I do think most users, myself included, ass= ume that feature xyz is fully supported if its associated module param exist. = Though I completely agree this is an unusual case since the MBEC/GMET aren't reall= y supported for non-nested, but KVM still consumes the module param. > This is I think the only point where I disagree, I think. No worries, I'm a-ok with this one as-is. And I can see it being useful as= a bisection point.