From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 457E96FA1 for ; Mon, 3 Apr 2023 14:34:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BFD8CC433D2; Mon, 3 Apr 2023 14:34:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1680532458; bh=tZgnvcGJbNLHeW0x2kbUNHiYwG547kNTzcdD1A7Wj6s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zM/30+zxdmILdldM/46tKQAQI/CRFl5Ik9o0srYG4leD60BwD/Ow6JO1DRLWzi1pi mK3+xhT7zeKzg/w3x5XqeVCl0YlSfYLhwAUfkSMUIQSgyn7IrV+sHN5J/MOu/Wdv4z 50WUTIMeiEroDE0XC+MKUmUGKfbRSML+G2O1k/h0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Marc Orr , Maxim Levitsky , Sean Christopherson , Alejandro Jimenez Subject: [PATCH 5.15 91/99] KVM: x86: Inject #GP on x2APIC WRMSR that sets reserved bits 63:32 Date: Mon, 3 Apr 2023 16:09:54 +0200 Message-Id: <20230403140406.783567564@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230403140356.079638751@linuxfoundation.org> References: <20230403140356.079638751@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Sean Christopherson commit ab52be1b310bcb39e6745d34a8f0e8475d67381a upstream. Reject attempts to set bits 63:32 for 32-bit x2APIC registers, i.e. all x2APIC registers except ICR. Per Intel's SDM: Non-zero writes (by WRMSR instruction) to reserved bits to these registers will raise a general protection fault exception Opportunistically fix a typo in a nearby comment. Reported-by: Marc Orr Cc: stable@vger.kernel.org Reviewed-by: Maxim Levitsky Link: https://lore.kernel.org/r/20230107011025.565472-3-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Alejandro Jimenez Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/lapic.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2802,6 +2802,10 @@ int kvm_x2apic_msr_write(struct kvm_vcpu /* if this is ICR write vector before command */ if (reg == APIC_ICR) kvm_lapic_reg_write(apic, APIC_ICR2, (u32)(data >> 32)); + else if (data >> 32) + /* Bits 63:32 are reserved in all other registers. */ + return 1; + return kvm_lapic_reg_write(apic, reg, (u32)data); } @@ -2836,6 +2840,10 @@ int kvm_hv_vapic_msr_write(struct kvm_vc /* if this is ICR write vector before command */ if (reg == APIC_ICR) kvm_lapic_reg_write(apic, APIC_ICR2, (u32)(data >> 32)); + else if (data >> 32) + /* Bits 63:32 are reserved in all other registers. */ + return 1; + return kvm_lapic_reg_write(apic, reg, (u32)data); }