From nobody Fri Dec 19 18:30:44 2025 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (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 7D24B13AD1C for ; Sat, 15 Feb 2025 01:14:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739582084; cv=none; b=C2buqB1sywupfkeUGyRxEqtvrFaOEsusBrkeN/UvHWjUIbAfkWcbBdJ/uZKlbh/YoRnH23gssOjbikUpGedF0F6zF2wglQSAkMiqvQOqE41+EOW37K7RcU96WanetWnHHo8UKPghozf5QHcm1rC7U+OiF/KgEDLaMcIs/sceENo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739582084; c=relaxed/simple; bh=JbnvHaDptxn9NsbJMw3UZ8db940ba/YMp/UB9zJLz0k=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=koTITtWESxza5VTaG1N67xO7OMJOuB8HtB+yLNyhbBYkxvYqeEgIH/FYiphQFr6J6LQrQRuUWVc5ks2EyNnfefHWh0tRfSbfh1a+JzPjbuEaEZZlTs0PxHd1J3yvid87/9n5tRDJp+2sNJynm23zmuOQoP9/Uwvqjay0m0++2sY= 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=BgE/8kVj; arc=none smtp.client-ip=209.85.216.74 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="BgE/8kVj" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-2f2a9f056a8so5473054a91.2 for ; Fri, 14 Feb 2025 17:14:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1739582083; x=1740186883; 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=Q49hFnWXm1R0ExDb7g/KnSF2lPa5FS0gZ3iojWO2T5A=; b=BgE/8kVj4LXa5SEfCCcYIYy2360/CFrjQFAzSybIVXQzBgjDZJjsAE8dBP0GzUMYUG Tn8JBpkdNp20LuepheOt6YiYKxD1mHin8pmpWObuv2PZpCh4Yf1AXqOyW74a54g4vPBm 1BoHm7JYU2xxp3ExJ0n6cpGgGuWs8R8Xg3olznGsHXRBs4sl+K0qJmsWRSF7eTl9kgnE v2JdCuxmMlS6fUBFs4ipUNeSu6FfZIqb3ZeBhd9v8UhWgdMUpdCeVYOLu2GAYggKvqTm JcHnKy0KmZklQy02hA53Ka3y/qqDzyd0z8vPiKLL/hNuA1/10spkGo/TCQjStPRggpPp bfFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1739582083; x=1740186883; 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=Q49hFnWXm1R0ExDb7g/KnSF2lPa5FS0gZ3iojWO2T5A=; b=oqCMU4rDou+PGGhZcct/xjyoWXwvc9BF5fHFuvomlkIGtkvUPe5W2qf+hX6sjz01Gr q5amdbbt6ocJVuJzQH9yaKUsVhGsUuf8P9EXTSMLtJsMmyO1UFynjsSoQfK2gdcmjGW7 4moGyat+UY97ofWUpEtTdwhRmehJX4brKlz/TP5qcga3trcqAvVJZcXxMrJWqirO56Y2 LWVEZiqoW5GNE4q3RPvRAVRBILiifnanHZ54ZR5sVhau8xWAnXdFkuu2N7nDkYGSqdrV xDFeaXPC0M8Dja0TtBgQl7aW6kRoVGNg4CYf9X30Rz116Gc9z0R2jhJkuo5ltygmKd4y 2qxg== X-Forwarded-Encrypted: i=1; AJvYcCW0K26rxTqHMW60Gz41rqYlaEC4gj+ZSnTo/nrsI3aMQJbCsalTnMhz2lGsaimXrkLLCehgZtYAJe886q0=@vger.kernel.org X-Gm-Message-State: AOJu0YyRoEviSTpZQEzx2s6UtTsBNprD5URnMg9JJq5t5Rm5WsuWu6vJ nZyrQRDMMg4Lh8XZphnql1GSQQsBpQDLMe7X4vDi+LXYVOQjbozjldgYB6APC0ubCvxstrAy/do eTA== X-Google-Smtp-Source: AGHT+IHBkyl4PIpFpkFkqS6pqT2rwD3MsxlYDyDhMSaF0m4JLwYlAZEuhy23IIj9HKSlsdXErMSDNcJbz7A= X-Received: from pjbnb2.prod.google.com ([2002:a17:90b:35c2:b0:2fc:c98:ea47]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:3949:b0:2ee:db8a:2a01 with SMTP id 98e67ed59e1d1-2fc41153d87mr1793706a91.30.1739582082789; Fri, 14 Feb 2025 17:14:42 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 14 Feb 2025 17:14:34 -0800 In-Reply-To: <20250215011437.1203084-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250215011437.1203084-1-seanjc@google.com> X-Mailer: git-send-email 2.48.1.601.g30ceb7b040-goog Message-ID: <20250215011437.1203084-3-seanjc@google.com> Subject: [PATCH v2 2/5] KVM: x86/xen: Add an #ifdef'd helper to detect writes to Xen MSR From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini , David Woodhouse , Paul Durrant Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Joao Martins , David Woodhouse Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add a helper to detect writes to the Xen hypercall page MSR, and provide a stub for CONFIG_KVM_XEN=3Dn to optimize out the check for kernels built without Xen support. Reviewed-by: Paul Durrant Reviewed-by: David Woodhouse Signed-off-by: Sean Christopherson --- arch/x86/kvm/x86.c | 2 +- arch/x86/kvm/xen.h | 10 ++++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 462a5cd6ac4a..12c60adb7349 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3738,7 +3738,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct = msr_data *msr_info) * page setup; it could incur locking paths which are not expected * if userspace sets the MSR in an unusual location. */ - if (msr && msr =3D=3D vcpu->kvm->arch.xen_hvm_config.msr && + if (kvm_xen_is_hypercall_page_msr(vcpu->kvm, msr) && !msr_info->host_initiated) return kvm_xen_write_hypercall_page(vcpu, data); =20 diff --git a/arch/x86/kvm/xen.h b/arch/x86/kvm/xen.h index f5841d9000ae..e92e06926f76 100644 --- a/arch/x86/kvm/xen.h +++ b/arch/x86/kvm/xen.h @@ -56,6 +56,11 @@ static inline bool kvm_xen_msr_enabled(struct kvm *kvm) kvm->arch.xen_hvm_config.msr; } =20 +static inline bool kvm_xen_is_hypercall_page_msr(struct kvm *kvm, u32 msr) +{ + return msr && msr =3D=3D kvm->arch.xen_hvm_config.msr; +} + static inline bool kvm_xen_hypercall_enabled(struct kvm *kvm) { return static_branch_unlikely(&kvm_xen_enabled.key) && @@ -124,6 +129,11 @@ static inline bool kvm_xen_msr_enabled(struct kvm *kvm) return false; } =20 +static inline bool kvm_xen_is_hypercall_page_msr(struct kvm *kvm, u32 msr) +{ + return false; +} + static inline bool kvm_xen_hypercall_enabled(struct kvm *kvm) { return false; --=20 2.48.1.601.g30ceb7b040-goog