From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f197.google.com (mail-pg1-f197.google.com [209.85.215.197]) by kanga.kvack.org (Postfix) with ESMTP id 6A7AE8E001A for ; Wed, 23 Jan 2019 09:17:48 -0500 (EST) Received: by mail-pg1-f197.google.com with SMTP id t26so1544579pgu.18 for ; Wed, 23 Jan 2019 06:17:48 -0800 (PST) Received: from userp2130.oracle.com (userp2130.oracle.com. [156.151.31.86]) by mx.google.com with ESMTPS id p23si18995046pgk.312.2019.01.23.06.17.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 23 Jan 2019 06:17:47 -0800 (PST) Date: Wed, 23 Jan 2019 09:16:35 -0500 From: Konrad Rzeszutek Wilk Subject: Re: [RFC PATCH v7 04/16] swiotlb: Map the buffer if it was unmapped by XPFO Message-ID: <20190123141614.GA19289@Konrads-MacBook-Pro.local> References: <98f9b9be522d694d5a52640dd1dfbdd14ca6f8e5.1547153058.git.khalid.aziz@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <98f9b9be522d694d5a52640dd1dfbdd14ca6f8e5.1547153058.git.khalid.aziz@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: Khalid Aziz Cc: juergh@gmail.com, tycho@tycho.ws, jsteckli@amazon.de, ak@linux.intel.com, torvalds@linux-foundation.org, liran.alon@oracle.com, keescook@google.com, Juerg Haefliger , deepa.srinivasan@oracle.com, chris.hyser@oracle.com, tyhicks@canonical.com, dwmw@amazon.co.uk, andrew.cooper3@citrix.com, jcm@redhat.com, boris.ostrovsky@oracle.com, kanth.ghatraju@oracle.com, joao.m.martins@oracle.com, jmattson@google.com, pradeep.vincent@oracle.com, john.haxby@oracle.com, tglx@linutronix.de, kirill.shutemov@linux.intel.com, hch@lst.de, steven.sistare@oracle.com, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Tycho Andersen On Thu, Jan 10, 2019 at 02:09:36PM -0700, Khalid Aziz wrote: > From: Juerg Haefliger > > v6: * guard against lookup_xpfo() returning NULL > > CC: Konrad Rzeszutek Wilk > Signed-off-by: Juerg Haefliger > Signed-off-by: Tycho Andersen > Signed-off-by: Khalid Aziz Reviewed-by: Konrad Rzeszutek Wilk > --- > include/linux/xpfo.h | 4 ++++ > kernel/dma/swiotlb.c | 3 ++- > mm/xpfo.c | 15 +++++++++++++++ > 3 files changed, 21 insertions(+), 1 deletion(-) > > diff --git a/include/linux/xpfo.h b/include/linux/xpfo.h > index a39259ce0174..e38b823f44e3 100644 > --- a/include/linux/xpfo.h > +++ b/include/linux/xpfo.h > @@ -35,6 +35,8 @@ void xpfo_kunmap(void *kaddr, struct page *page); > void xpfo_alloc_pages(struct page *page, int order, gfp_t gfp); > void xpfo_free_pages(struct page *page, int order); > > +bool xpfo_page_is_unmapped(struct page *page); > + > #else /* !CONFIG_XPFO */ > > static inline void xpfo_kmap(void *kaddr, struct page *page) { } > @@ -42,6 +44,8 @@ static inline void xpfo_kunmap(void *kaddr, struct page *page) { } > static inline void xpfo_alloc_pages(struct page *page, int order, gfp_t gfp) { } > static inline void xpfo_free_pages(struct page *page, int order) { } > > +static inline bool xpfo_page_is_unmapped(struct page *page) { return false; } > + > #endif /* CONFIG_XPFO */ > > #endif /* _LINUX_XPFO_H */ > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index 045930e32c0e..820a54b57491 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -396,8 +396,9 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr, > { > unsigned long pfn = PFN_DOWN(orig_addr); > unsigned char *vaddr = phys_to_virt(tlb_addr); > + struct page *page = pfn_to_page(pfn); > > - if (PageHighMem(pfn_to_page(pfn))) { > + if (PageHighMem(page) || xpfo_page_is_unmapped(page)) { > /* The buffer does not have a mapping. Map it in and copy */ > unsigned int offset = orig_addr & ~PAGE_MASK; > char *buffer; > diff --git a/mm/xpfo.c b/mm/xpfo.c > index bff24afcaa2e..cdbcbac582d5 100644 > --- a/mm/xpfo.c > +++ b/mm/xpfo.c > @@ -220,3 +220,18 @@ void xpfo_kunmap(void *kaddr, struct page *page) > spin_unlock(&xpfo->maplock); > } > EXPORT_SYMBOL(xpfo_kunmap); > + > +bool xpfo_page_is_unmapped(struct page *page) > +{ > + struct xpfo *xpfo; > + > + if (!static_branch_unlikely(&xpfo_inited)) > + return false; > + > + xpfo = lookup_xpfo(page); > + if (unlikely(!xpfo) && !xpfo->inited) > + return false; > + > + return test_bit(XPFO_PAGE_UNMAPPED, &xpfo->flags); > +} > +EXPORT_SYMBOL(xpfo_page_is_unmapped); > -- > 2.17.1 >