From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Lendacky Subject: Re: [RFC Part1 PATCH v3 07/17] x86/mm: Include SEV for encryption memory attribute changes Date: Thu, 17 Aug 2017 13:21:39 -0500 Message-ID: <786b615a-941c-ae83-e02b-01ece58af5b3@amd.com> References: <20170724190757.11278-1-brijesh.singh@amd.com> <20170724190757.11278-8-brijesh.singh@amd.com> <20170727145841.GG28553@nazgul.tnic> <063D6719AE5E284EB5DD2968C1650D6DD0045508@AcuExch.aculab.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6DD0045508-VkEWCZq2GCInGFn1LkZF6NBPR1lH4CV8@public.gmane.org> Content-Language: en-US Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: David Laight , 'Borislav Petkov' , Brijesh Singh Cc: "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , =?UTF-8?Q?Radim_Krcm=c3=a1r?= , "kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Fenghua Yu , Matt Fleming , David Howells , Paul Mackerras , "H . Peter Anvin" , Christoph Lameter , Jonathan Corbet , "x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" , Piotr Luc , Ingo Molnar , Dave Airlie , Laura Abbott , Kees Cook , Arnd Bergmann , Konrad Rzeszutek Wilk , Reza Arbab , Andy Lutomirski List-Id: linux-efi@vger.kernel.org On 7/28/2017 3:47 AM, David Laight wrote: > From: Borislav Petkov >> Sent: 27 July 2017 15:59 >> On Mon, Jul 24, 2017 at 02:07:47PM -0500, Brijesh Singh wrote: >>> From: Tom Lendacky >>> >>> The current code checks only for sme_active() when determining whether >>> to perform the encryption attribute change. Include sev_active() in this >>> check so that memory attribute changes can occur under SME and SEV. >>> >>> Signed-off-by: Tom Lendacky >>> Signed-off-by: Brijesh Singh >>> --- >>> arch/x86/mm/pageattr.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c >>> index dfb7d65..b726b23 100644 >>> --- a/arch/x86/mm/pageattr.c >>> +++ b/arch/x86/mm/pageattr.c >>> @@ -1781,8 +1781,8 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc) >>> unsigned long start; >>> int ret; >>> >>> - /* Nothing to do if the SME is not active */ >>> - if (!sme_active()) >>> + /* Nothing to do if SME and SEV are not active */ >>> + if (!sme_active() && !sev_active()) >> >> This is the second place which does >> >> if (!SME && !SEV) >> >> I wonder if, instead of sprinking those, we should have a >> >> if (mem_enc_active()) >> >> or so which unifies all those memory encryption logic tests and makes >> the code more straightforward for readers who don't have to pay >> attention to SME vs SEV ... > > If any of the code paths are 'hot' it would make sense to be checking > a single memory location. The function would check a single variable/memory location and making it an inline function would accomplish that. Thanks, Tom > > David >