From patchwork Mon Jan 15 12:56:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 13519600 Received: from mail.xenproject.org (mail.xenproject.org [104.130.215.37]) (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 B2CD7175A5; Mon, 15 Jan 2024 13:09:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=xen.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=xen.org header.i=@xen.org header.b="MHrFpF5I" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:MIME-Version:References: In-Reply-To:Message-Id:Date:Subject:To:From; bh=TGoYbz9rXouSd9WFL4ciI9FwoKQtj7ZUq9cOLPJ0RRg=; b=MHrFpF5IJ+PfFQlCE294QZkLS7 j1/pDVM5hSybbNPSM6bz27B/hEc8rQyVvvivfowOtblwXmtVBmpjhVNlW+rsILZE79dR237K3WYe4 sWL/GJ3zw5LqApPZ60YVEe5o0HHNWZ/i5HLLuN8wc99AFrvl6Mtrl/xbbb4PtGW9BywY=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1rPMiY-00035c-L6; Mon, 15 Jan 2024 13:09:30 +0000 Received: from 54-240-197-231.amazon.com ([54.240.197.231] helo=REM-PW02S00X.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rPMXN-0002kM-4Y; Mon, 15 Jan 2024 12:57:57 +0000 From: Paul Durrant To: Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , David Woodhouse , Paul Durrant , Shuah Khan , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v12 10/20] KVM: xen: re-initialize shared_info if guest (32/64-bit) mode is set Date: Mon, 15 Jan 2024 12:56:57 +0000 Message-Id: <20240115125707.1183-11-paul@xen.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240115125707.1183-1-paul@xen.org> References: <20240115125707.1183-1-paul@xen.org> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Paul Durrant If the shared_info PFN cache has already been initialized then the content of the shared_info page needs to be re-initialized whenever the guest mode is (re)set. Setting the guest mode is either done explicitly by the VMM via the KVM_XEN_ATTR_TYPE_LONG_MODE attribute, or implicitly when the guest writes the MSR to set up the hypercall page. Signed-off-by: Paul Durrant Reviewed-by: David Woodhouse --- Cc: Sean Christopherson Cc: Paolo Bonzini Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: David Woodhouse Cc: x86@kernel.org v12: - Fix missing update of return value if mode is not actually changed. v11: - Drop the hunk removing the call to kvm_xen_shared_info_init() when KVM_XEN_ATTR_TYPE_SHARED_INFO is set; it was a mistake and causes self- test failures. v10: - New in this version. --- arch/x86/kvm/xen.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index df53fea73747..d595d476a5b3 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -625,8 +625,16 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) } else { mutex_lock(&kvm->arch.xen.xen_lock); kvm->arch.xen.long_mode = !!data->u.long_mode; + + /* + * Re-initialize shared_info to put the wallclock in the + * correct place. Whilst it's not necessary to do this + * unless the mode is actually changed, it does no harm + * to make the call anyway. + */ + r = kvm->arch.xen.shinfo_cache.active ? + kvm_xen_shared_info_init(kvm) : 0; mutex_unlock(&kvm->arch.xen.xen_lock); - r = 0; } break; @@ -1101,9 +1109,24 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data) u32 page_num = data & ~PAGE_MASK; u64 page_addr = data & PAGE_MASK; bool lm = is_long_mode(vcpu); + int r = 0; + + mutex_lock(&kvm->arch.xen.xen_lock); + if (kvm->arch.xen.long_mode != lm) { + kvm->arch.xen.long_mode = lm; + + /* + * Re-initialize shared_info to put the wallclock in the + * correct place. + */ + if (kvm->arch.xen.shinfo_cache.active && + kvm_xen_shared_info_init(kvm)) + r = 1; + } + mutex_unlock(&kvm->arch.xen.xen_lock); - /* Latch long_mode for shared_info pages etc. */ - vcpu->kvm->arch.xen.long_mode = lm; + if (r) + return r; /* * If Xen hypercall intercept is enabled, fill the hypercall