From nobody Mon Feb 9 23:15:45 2026 Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) (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 6331B1448D7 for ; Tue, 23 Apr 2024 22:15:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713910532; cv=none; b=sV29L791tCaPf69muXKxJSsUQpqfygxi5aHLUaADXHR2J5Qp5j9W3dtUw5Y/kyJ5eprBBta0blwc8s7r9GKGjM5M9lWOLZan6NiKGHTZIIZwSPHbErMnaFj+nOWtC10EzbFbf8yGGtpxn6UG+va9QcyQw1ObJL/BYDkBeVeVZck= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713910532; c=relaxed/simple; bh=xE1KUFK4G+p/d3CyfBOgMCJHlIiny9RJ4lxmT/9Dm04=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=W80CRn0IiKycSZ0oqvL2ZCKrQ0YdCv0sS6cJKRqX0H7RQ8sIQdEUOBSsOw9f5ryHhHt3fIPChpyMuqtDcR3dzh8KXkw+aXBuRwYy72tsQntWRLYvEMExU+9y8PxZPLaSnnsSbHlpETUhw0YKnFTl5Ipxahv/tRNzKTxSPN6v6xM= 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=FkA08b1r; arc=none smtp.client-ip=209.85.128.201 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="FkA08b1r" Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-615073c8dfbso113433217b3.1 for ; Tue, 23 Apr 2024 15:15:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1713910530; x=1714515330; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=925/3TcbmBk8/dgvobnmcuIGRsrdaR6MRTRxQEFXUJk=; b=FkA08b1rtaw1mLOXxakIBnKEdlGtW4Zrn9fbVGt97lrntoEGBMRj8ZdMCyhYe+m2H2 LgVtVOhvmd1wUHIrVw+WtH10m4oV8Idm914gUIeLsGfn8/FlBpmVX561ZfqF9P4tHcLO IfKW12JdEqsqqNFDSghsVNHEa/Ubtu6sD2AqDfie/lBe+b5U1NUnRLdkcgV3bfQzl2op GtkJi4H1MDyymGw+z3OCzzjPzGLAkskBayBSC/G++qV7bwKXfzExHbK+anYUPnqjuzic cw8bufB0UFgYfawnOteQ8VogZWe9bkm6VZvLV1pHRDRcfRXUlFZLfpCGMbSSeD5GziXX ijwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1713910530; x=1714515330; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=925/3TcbmBk8/dgvobnmcuIGRsrdaR6MRTRxQEFXUJk=; b=SGVDd7yhJJyC12Vtlxp3qjs+U545AWk7bmzbkuDik4aINQEWNYlYyOkWcO1gB6YYML txKZb1vb+vp4tPGLCMk7ajzlXe3at2oqIBsmb+ngjKgOWjXFDdkA20y7Y6+qb/DwMwDq kEYpSyqDvmrnVpot8qLpi1KmO87YhgwpkugP9TwW8ET/Powox++MeIMqwGTwG7QvlAT2 45n6aTTH9kxSO1GaCiittRwHGfRVauC9VIYeoSZ5TvA8yy98B/0p/FOaaKJlhVjpztbE YoicCO0I4kvPh7IuZZ6GzO/YRKQek5+3QKrUG2MvarxKTymg1w6nl3dARUQf4y/u8f+5 AljA== X-Forwarded-Encrypted: i=1; AJvYcCX7fqKiYLNBZT2XLm4Z7yUVzG1PtUL63MadIBcsLEpp1Pb74EzICITBGvxMe/KuxOAy2/DAfU895LGS5c+xeAiscUabqUd+Qne5TfYl X-Gm-Message-State: AOJu0YyH0Gmh6rcdk3OY93CEFnYccWYqIgckCN7HMdGuM8N7+opgRkt6 HzpGjBxdTlbfawO5CnkGYTLYQEU+uMNfzJCAL75AqvNpcNoRZh8j+Gt+p3LcUC8uIV3oFuwg1qW mzw== X-Google-Smtp-Source: AGHT+IFX0P+LbQNZxR5CLCQuMpKsdOUSE0MG1uSUj4yZFqITsFafOfA4cmVbD+WTu75aActV8Bz4bt1CoZc= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:1027:b0:de0:ecc6:4681 with SMTP id x7-20020a056902102700b00de0ecc64681mr100790ybt.1.1713910530470; Tue, 23 Apr 2024 15:15:30 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 23 Apr 2024 15:15:20 -0700 In-Reply-To: <20240423221521.2923759-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240423221521.2923759-1-seanjc@google.com> X-Mailer: git-send-email 2.44.0.769.g3c40516874-goog Message-ID: <20240423221521.2923759-4-seanjc@google.com> Subject: [PATCH 3/4] KVM: x86/mmu: Snapshot shadow_phys_bits when kvm.ko is loaded From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Snapshot shadow_phys_bits when kvm.ko is loaded, not when a vendor module is loaded, to guard against usage of shadow_phys_bits before it is initialized. The computation isn't vendor specific in any way, i.e. there there is no reason to wait to snapshot the value until a vendor module is loaded, nor is there any reason to recompute the value every time a vendor module is loaded. Opportunistically convert it from "read mostly" to "read-only after init". Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu.h | 2 +- arch/x86/kvm/mmu/spte.c | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index b410a227c601..ef970aea26e7 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -61,7 +61,7 @@ static __always_inline u64 rsvd_bits(int s, int e) * The number of non-reserved physical address bits irrespective of featur= es * that repurpose legal bits, e.g. MKTME. */ -extern u8 __read_mostly shadow_phys_bits; +extern u8 __ro_after_init shadow_phys_bits; =20 static inline gfn_t kvm_mmu_max_gfn(void) { diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index 6c7ab3aa6aa7..927f4abbe973 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -43,7 +43,7 @@ u64 __read_mostly shadow_acc_track_mask; u64 __read_mostly shadow_nonpresent_or_rsvd_mask; u64 __read_mostly shadow_nonpresent_or_rsvd_lower_gfn_mask; =20 -u8 __read_mostly shadow_phys_bits; +u8 __ro_after_init shadow_phys_bits; =20 void __init kvm_mmu_spte_module_init(void) { @@ -55,6 +55,8 @@ void __init kvm_mmu_spte_module_init(void) * will change when the vendor module is (re)loaded. */ allow_mmio_caching =3D enable_mmio_caching; + + shadow_phys_bits =3D kvm_get_shadow_phys_bits(); } =20 static u64 generation_mmio_spte_mask(u64 gen) @@ -439,8 +441,6 @@ void kvm_mmu_reset_all_pte_masks(void) u8 low_phys_bits; u64 mask; =20 - shadow_phys_bits =3D kvm_get_shadow_phys_bits(); - /* * If the CPU has 46 or less physical address bits, then set an * appropriate mask to guard against L1TF attacks. Otherwise, it is --=20 2.44.0.769.g3c40516874-goog