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[23.128.96.18]) by mx.google.com with ESMTP id ce9si7025037edb.70.2020.06.26.10.29.11; Fri, 26 Jun 2020 10:29:34 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b="tFtDTtZ/"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727041AbgFZRYm (ORCPT + 99 others); Fri, 26 Jun 2020 13:24:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:41018 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726885AbgFZRYf (ORCPT ); Fri, 26 Jun 2020 13:24:35 -0400 Received: from localhost (c-67-180-165-146.hsd1.ca.comcast.net [67.180.165.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 219F620836; Fri, 26 Jun 2020 17:24:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593192275; bh=F/VWExg6XQ5+v2BiFiVfoHATO51UpO4eHrdk+RYhIUU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tFtDTtZ/LsvC48ct+GASS5dYzV+oh45HDZLwn8W3k1fWIUdg+T/tBuo9ctlvzon06 Gah/UFGCtmQKCa6W/wCzF1ENDGCXIKWCG8g/1NtKm0BUJ/I2JBiOlahJe7oBNreGSc Xks4oexOZg3SXRO/rGaWduGPDomsDDOCo7x4YXBU= From: Andy Lutomirski To: x86@kernel.org Cc: Sasha Levin , linux-kernel@vger.kernel.org, Andrew Cooper , Juergen Gross , Andy Lutomirski , Boris Ostrovsky , Stefano Stabellini , xen-devel@lists.xenproject.org Subject: [PATCH fsgsbase v2 4/4] x86/fsgsbase: Fix Xen PV support Date: Fri, 26 Jun 2020 10:24:30 -0700 Message-Id: X-Mailer: git-send-email 2.25.4 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Xen PV, SWAPGS doesn't work. Teach __rdfsbase_inactive() and __wrgsbase_inactive() to use rdmsrl()/wrmsrl() on Xen PV. The Xen pvop code will understand this and issue the correct hypercalls. Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Stefano Stabellini Cc: xen-devel@lists.xenproject.org Signed-off-by: Andy Lutomirski --- arch/x86/kernel/process_64.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index cb8e37d3acaa..457d02aa10d8 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -163,9 +163,13 @@ static noinstr unsigned long __rdgsbase_inactive(void) lockdep_assert_irqs_disabled(); - native_swapgs(); - gsbase = rdgsbase(); - native_swapgs(); + if (!static_cpu_has(X86_FEATURE_XENPV)) { + native_swapgs(); + gsbase = rdgsbase(); + native_swapgs(); + } else { + rdmsrl(MSR_KERNEL_GS_BASE, gsbase); + } return gsbase; } @@ -182,9 +186,13 @@ static noinstr void __wrgsbase_inactive(unsigned long gsbase) { lockdep_assert_irqs_disabled(); - native_swapgs(); - wrgsbase(gsbase); - native_swapgs(); + if (!static_cpu_has(X86_FEATURE_XENPV)) { + native_swapgs(); + wrgsbase(gsbase); + native_swapgs(); + } else { + wrmsrl(MSR_KERNEL_GS_BASE, gsbase); + } } /* -- 2.25.4