From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: Re: [PATCH v7 07/36] x86/mm: Don't use phys_to_virt in ioremap() if SME is active Date: Wed, 21 Jun 2017 09:37:39 +0200 (CEST) Message-ID: References: <20170616184947.18967.84890.stgit@tlendack-t1.amdoffice.net> <20170616185104.18967.7867.stgit@tlendack-t1.amdoffice.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: <20170616185104.18967.7867.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Tom Lendacky Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kasan-dev-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, xen-devel-GuqFBffKawuEi8DpZVb4nw@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Brijesh Singh , Toshimitsu Kani , =?ISO-8859-2?Q?Radim_Kr=E8m=E1=F8?= , Matt Fleming , Alexander Potapenko , "H. Peter Anvin" , Larry Woodman , Jonathan Corbet , Joerg Roedel , "Michael S. Tsirkin" , Ingo Molnar , Andrey Ryabinin , Dave List-Id: linux-efi@vger.kernel.org On Fri, 16 Jun 2017, Tom Lendacky wrote: > Currently there is a check if the address being mapped is in the ISA > range (is_ISA_range()), and if it is then phys_to_virt() is used to > perform the mapping. When SME is active, however, this will result > in the mapping having the encryption bit set when it is expected that > an ioremap() should not have the encryption bit set. So only use the > phys_to_virt() function if SME is not active > > Reviewed-by: Borislav Petkov > Signed-off-by: Tom Lendacky > --- > arch/x86/mm/ioremap.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c > index 4c1b5fd..a382ba9 100644 > --- a/arch/x86/mm/ioremap.c > +++ b/arch/x86/mm/ioremap.c > @@ -13,6 +13,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -106,9 +107,11 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, > } > > /* > - * Don't remap the low PCI/ISA area, it's always mapped.. > + * Don't remap the low PCI/ISA area, it's always mapped. > + * But if SME is active, skip this so that the encryption bit > + * doesn't get set. > */ > - if (is_ISA_range(phys_addr, last_addr)) > + if (is_ISA_range(phys_addr, last_addr) && !sme_active()) > return (__force void __iomem *)phys_to_virt(phys_addr); More thoughts about that. Making this conditional on !sme_active() is not the best idea. I'd rather remove that whole thing and make it unconditional so the code pathes get always exercised and any subtle wreckage is detected on a broader base and not only on that hard to access and debug SME capable machine owned by Joe User. Thanks, tglx