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Date: Fri, 28 Jul 2017 08:47:30 +0000 From: David Laight <David.Laight@...LAB.COM> To: 'Borislav Petkov' <bp@...e.de>, Brijesh Singh <brijesh.singh@....com> CC: "linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>, Radim Krcmár <rkrcmar@...hat.com>, "kvm@...r.kernel.org" <kvm@...r.kernel.org>, Fenghua Yu <fenghua.yu@...el.com>, Matt Fleming <matt@...eblueprint.co.uk>, David Howells <dhowells@...hat.com>, "Paul Mackerras" <paulus@...ba.org>, "H . Peter Anvin" <hpa@...or.com>, "Christoph Lameter" <cl@...ux.com>, Jonathan Corbet <corbet@....net>, "x86@...nel.org" <x86@...nel.org>, Piotr Luc <piotr.luc@...el.com>, Ingo Molnar <mingo@...hat.com>, Dave Airlie <airlied@...hat.com>, Laura Abbott <labbott@...hat.com>, Tom Lendacky <thomas.lendacky@....com>, Kees Cook <keescook@...omium.org>, Arnd Bergmann <arnd@...db.de>, Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>, Reza Arbab <arbab@...ux.vnet.ibm.com>, "Andy Lutomirski" <luto@...nel.org>, Thomas Gleixner <tglx@...utronix.de>, "Tony Luck" <tony.luck@...el.com>, Ard Biesheuvel <ard.biesheuvel@...aro.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Eric Biederman <ebiederm@...ssion.com>, Tejun Heo <tj@...nel.org>, Paolo Bonzini <pbonzini@...hat.com>, Andrew Morton <akpm@...ux-foundation.org>, "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>, "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>, Lu Baolu <baolu.lu@...ux.intel.com> Subject: RE: [RFC Part1 PATCH v3 07/17] x86/mm: Include SEV for encryption memory attribute changes 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 <thomas.lendacky@....com> > > > > 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 <thomas.lendacky@....com> > > Signed-off-by: Brijesh Singh <brijesh.singh@....com> > > --- > > 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. David
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