From nobody Mon Feb 9 21:03:38 2026 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 D622F26E716 for ; Tue, 10 Jun 2025 22:58:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749596315; cv=none; b=tRv23WpbSAIBrN5dsmI6L5zeHZS3GbWAu2Bd2BJOf84YyMlDEp9ujtJ39p5zQ/b15yvf0SGTIw70CElIZtFEMJzIFr67q1Vi5OvBJ0t0B2/6QI4gEyetgqVkEA/bvkSK429BU2XNrRaT9oLTxHK6k7no8kHYWTZnS+SmoQyjglI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749596315; c=relaxed/simple; bh=jiZmlQeeZHjv8j7JWaCkYOsUvUOPi3J9ClLWUxwWMQ4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=hSE3oRreAJ9qStrOsjtn30HW3AiTUeSonVa4xvexo14KqJQvkRW/ipiYFa649nuht4S6n9q9w84vqUl/fM+KDJVt2UGfiBlBdlsKO3RnpdJo8/Ce8rUgTgMUzIQwRg+fUAVPEp7qyU7YYkTAvqcP3JFJ28u/9SUc4KhwTe+9N1Y= 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=bPPtYFuJ; arc=none smtp.client-ip=209.85.214.202 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="bPPtYFuJ" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-23494a515e3so42809175ad.2 for ; Tue, 10 Jun 2025 15:58:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1749596313; x=1750201113; 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=izOjJ2HeWMTKGvvKPd+weoqGV6BoeCSaINzg8XvWVDQ=; b=bPPtYFuJjUpw01SILGj/p3x0pfYSoXpbP4gQLsbYxsvtlggpNDh8vgvQusIjwjc1UG gKX6So54HjT/f2rYgfH8k3WxFMeNPNIQZTwtAOaQDtWPwHMchXndxRHPKP0z+whkaaHW yPuvC8Ui0cd+FEZ4gc0QFgeO9lhbocWgL1O3y27KNhFbN1576vOtEJsUIMI2cUjPjLxk 64/P52I/IncG0H6w7dV3oacdOS39xfKtghGdjDFvtHNimtfcySePtfWMdbttf/OVfqRQ H6sA+dv0LGShPElwt+ykxzYoCWIq5NT/3x73bWNH8KE8p+jxb4CxkwPQuoE/EfEX6IOH hRjg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1749596313; x=1750201113; 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=izOjJ2HeWMTKGvvKPd+weoqGV6BoeCSaINzg8XvWVDQ=; b=D+v7Y38ryftXl8dRLkHKx0M/E+o52O52DgG5dWYsGrRFMJufqxaaJshCdYglSVvitm h2Pn2MCds1eLfV+r92OnDww6LHdZxOElk+7U7RQJUSEki43VtqR7ndOeiduuAfsfEsWT EojIdf06Ch5ohhpM8kT8i8jI1pGIYoIYdeCdu0VcgGRzPeXJfhJQ/nYOYl45I8h9cgCB QPUuUAUmiTtGXBdgUdgeMNMatZlDXUBHAJ+uhqNFAG+j56BVkQSEl/MZbiZA1ytNKZip Plkxrjo9EcktiM6JcHknSxYfQSXfh/m7HzeT81+WOaEboAIAuTLZ9mLmizXhBdxb3TIX N5jw== X-Forwarded-Encrypted: i=1; AJvYcCXixcwq6+aFBZzqKV1b4stCfGkOkMd2n/w4l81H3/NvQR10g9gN5tmT2/E0Gf5jxiJvFNBV9RDpaTDBQLA=@vger.kernel.org X-Gm-Message-State: AOJu0Yy2I5Z+jdx5NSgMtQtnQ+r37phKYa7vStZlIRQmRl28DkyKPM0a LkJvRueUFAfBAuDnTKOg7lfX501TH3liDAv8gNoEB3v+r+lfP4hMcubbV0We+PgQmUkatOL6UnA 42oIs2Q== X-Google-Smtp-Source: AGHT+IFGOj6HuWIr46kZTUddMM4ANW6v8OEb2ufDZkJPU2sF80cAp+a0btxYkhyYdPaDQ3eUlWL4PqPkgXg= X-Received: from plbmu14.prod.google.com ([2002:a17:903:b4e:b0:234:d7c5:a0e3]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:32c6:b0:234:9052:2be6 with SMTP id d9443c01a7336-23641b2919fmr13630285ad.41.1749596313412; Tue, 10 Jun 2025 15:58:33 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 10 Jun 2025 15:57:36 -0700 In-Reply-To: <20250610225737.156318-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250610225737.156318-1-seanjc@google.com> X-Mailer: git-send-email 2.50.0.rc0.642.g800a2b2222-goog Message-ID: <20250610225737.156318-32-seanjc@google.com> Subject: [PATCH v2 31/32] KVM: x86: Simplify userspace filter logic when disabling MSR interception From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Gao , Borislav Petkov , Xin Li , Dapeng Mi , Francesco Lavra , Manali Shukla Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Refactor {svm,vmx}_disable_intercept_for_msr() to simplify the handling of userspace filters that disallow access to an MSR. The more complicated logic is no longer needed or justified now that KVM recalculates all MSR intercepts on a userspace MSR filter change, i.e. now that KVM doesn't need to also update shadow bitmaps. No functional change intended. Suggested-by: Dapeng Mi Signed-off-by: Sean Christopherson Reviewed-by: Dapeng Mi --- arch/x86/kvm/svm/svm.c | 24 ++++++++++-------------- arch/x86/kvm/vmx/vmx.c | 24 ++++++++++-------------- 2 files changed, 20 insertions(+), 28 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index e3c49c763225..5453478d1ca3 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -691,24 +691,20 @@ void svm_disable_intercept_for_msr(struct kvm_vcpu *v= cpu, u32 msr, int type) void *msrpm =3D svm->msrpm; =20 /* Don't disable interception for MSRs userspace wants to handle. */ - if ((type & MSR_TYPE_R) && - !kvm_msr_allowed(vcpu, msr, KVM_MSR_FILTER_READ)) { - svm_set_msr_bitmap_read(msrpm, msr); - type &=3D ~MSR_TYPE_R; + if (type & MSR_TYPE_R) { + if (kvm_msr_allowed(vcpu, msr, KVM_MSR_FILTER_READ)) + svm_clear_msr_bitmap_read(msrpm, msr); + else + svm_set_msr_bitmap_read(msrpm, msr); } =20 - if ((type & MSR_TYPE_W) && - !kvm_msr_allowed(vcpu, msr, KVM_MSR_FILTER_WRITE)) { - svm_set_msr_bitmap_write(msrpm, msr); - type &=3D ~MSR_TYPE_W; + if (type & MSR_TYPE_W) { + if (kvm_msr_allowed(vcpu, msr, KVM_MSR_FILTER_WRITE)) + svm_clear_msr_bitmap_write(msrpm, msr); + else + svm_set_msr_bitmap_write(msrpm, msr); } =20 - if (type & MSR_TYPE_R) - svm_clear_msr_bitmap_read(msrpm, msr); - - if (type & MSR_TYPE_W) - svm_clear_msr_bitmap_write(msrpm, msr); - svm_hv_vmcb_dirty_nested_enlightenments(vcpu); svm->nested.force_msr_bitmap_recalc =3D true; } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index bdff81f8288d..277c6b5b5d5f 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3962,23 +3962,19 @@ void vmx_disable_intercept_for_msr(struct kvm_vcpu = *vcpu, u32 msr, int type) =20 vmx_msr_bitmap_l01_changed(vmx); =20 - if ((type & MSR_TYPE_R) && - !kvm_msr_allowed(vcpu, msr, KVM_MSR_FILTER_READ)) { - vmx_set_msr_bitmap_read(msr_bitmap, msr); - type &=3D ~MSR_TYPE_R; + if (type & MSR_TYPE_R) { + if (kvm_msr_allowed(vcpu, msr, KVM_MSR_FILTER_READ)) + vmx_clear_msr_bitmap_read(msr_bitmap, msr); + else + vmx_set_msr_bitmap_read(msr_bitmap, msr); } =20 - if ((type & MSR_TYPE_W) && - !kvm_msr_allowed(vcpu, msr, KVM_MSR_FILTER_WRITE)) { - vmx_set_msr_bitmap_write(msr_bitmap, msr); - type &=3D ~MSR_TYPE_W; + if (type & MSR_TYPE_W) { + if (kvm_msr_allowed(vcpu, msr, KVM_MSR_FILTER_WRITE)) + vmx_clear_msr_bitmap_write(msr_bitmap, msr); + else + vmx_set_msr_bitmap_write(msr_bitmap, msr); } - - if (type & MSR_TYPE_R) - vmx_clear_msr_bitmap_read(msr_bitmap, msr); - - if (type & MSR_TYPE_W) - vmx_clear_msr_bitmap_write(msr_bitmap, msr); } =20 void vmx_enable_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type) --=20 2.50.0.rc0.642.g800a2b2222-goog