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From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Mike Rapoport <rppt@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	David Rientjes <rientjes@google.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Kees Cook <keescook@chromium.org>, Will Drewry <wad@chromium.org>,
	"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
	"Kleen, Andi" <andi.kleen@intel.com>,
	x86@kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [RFC 07/16] KVM: mm: Introduce VM_KVM_PROTECTED
Date: Wed, 27 May 2020 01:01:55 +0300
Message-ID: <20200526220155.34xmakrh7ipqynht@box> (raw)
In-Reply-To: <20200526061552.GD13247@kernel.org>

On Tue, May 26, 2020 at 09:15:52AM +0300, Mike Rapoport wrote:
> On Fri, May 22, 2020 at 03:52:05PM +0300, Kirill A. Shutemov wrote:
> > The new VMA flag that indicate a VMA that is not accessible to userspace
> > but usable by kernel with GUP if FOLL_KVM is specified.
> > 
> > The FOLL_KVM is only used in the KVM code. The code has to know how to
> > deal with such pages.
> > 
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > ---
> >  include/linux/mm.h  |  8 ++++++++
> >  mm/gup.c            | 20 ++++++++++++++++----
> >  mm/huge_memory.c    | 20 ++++++++++++++++----
> >  mm/memory.c         |  3 +++
> >  mm/mmap.c           |  3 +++
> >  virt/kvm/async_pf.c |  4 ++--
> >  virt/kvm/kvm_main.c |  9 +++++----
> >  7 files changed, 53 insertions(+), 14 deletions(-)
> > 
> > diff --git a/include/linux/mm.h b/include/linux/mm.h
> > index e1882eec1752..4f7195365cc0 100644
> > --- a/include/linux/mm.h
> > +++ b/include/linux/mm.h
> > @@ -329,6 +329,8 @@ extern unsigned int kobjsize(const void *objp);
> >  # define VM_MAPPED_COPY	VM_ARCH_1	/* T if mapped copy of data (nommu mmap) */
> >  #endif
> >  
> > +#define VM_KVM_PROTECTED 0
> 
> With all the ideas about removing pages from the direct mapi floating
> around I wouldn't limit this to KVM.
> 
> VM_NOT_IN_DIRECT_MAP would describe such areas better, but I realise
> it's very far from perfect and nothing better does not comes to mind :)

I don't like VM_NOT_IN_DIRECT_MAP.

It's not only about direct mapping, but about userspace mapping as well.
For the same reason other naming proposals don't fit as well.

> > diff --git a/mm/mmap.c b/mm/mmap.c
> > index f609e9ec4a25..d56c3f6efc99 100644
> > --- a/mm/mmap.c
> > +++ b/mm/mmap.c
> > @@ -112,6 +112,9 @@ pgprot_t vm_get_page_prot(unsigned long vm_flags)
> >  				(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
> >  			pgprot_val(arch_vm_get_page_prot(vm_flags)));
> >  
> > +	if (vm_flags & VM_KVM_PROTECTED)
> > +		ret = PAGE_NONE;
> 
> Nit: vma_is_kvm_protected()?

Which VMA? :P

-- 
 Kirill A. Shutemov

  reply index

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-22 12:51 [RFC 00/16] KVM protected memory extension Kirill A. Shutemov
2020-05-22 12:51 ` [RFC 01/16] x86/mm: Move force_dma_unencrypted() to common code Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 02/16] x86/kvm: Introduce KVM memory protection feature Kirill A. Shutemov
2020-05-25 14:58   ` Vitaly Kuznetsov
2020-05-25 15:15     ` Kirill A. Shutemov
2020-05-27  5:03       ` Sean Christopherson
2020-05-27  8:39         ` Vitaly Kuznetsov
2020-05-27  8:52           ` Sean Christopherson
2020-06-03  2:09           ` Huang, Kai
2020-06-03 11:14             ` Vitaly Kuznetsov
2020-05-22 12:52 ` [RFC 03/16] x86/kvm: Make DMA pages shared Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 04/16] x86/kvm: Use bounce buffers for KVM memory protection Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 05/16] x86/kvm: Make VirtIO use DMA API in KVM guest Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 06/16] KVM: Use GUP instead of copy_from/to_user() to access guest memory Kirill A. Shutemov
2020-05-25 15:08   ` Vitaly Kuznetsov
2020-05-25 15:17     ` Kirill A. Shutemov
2020-06-01 16:35       ` Paolo Bonzini
2020-06-02 13:33         ` Kirill A. Shutemov
2020-05-26  6:14   ` Mike Rapoport
2020-05-26 21:56     ` Kirill A. Shutemov
2020-05-29 15:24   ` Kees Cook
2020-05-22 12:52 ` [RFC 07/16] KVM: mm: Introduce VM_KVM_PROTECTED Kirill A. Shutemov
2020-05-26  6:15   ` Mike Rapoport
2020-05-26 22:01     ` Kirill A. Shutemov [this message]
2020-05-26  6:40   ` John Hubbard
2020-05-26 22:04     ` Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 08/16] KVM: x86: Use GUP for page walk instead of __get_user() Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 09/16] KVM: Protected memory extension Kirill A. Shutemov
2020-05-25 15:26   ` Vitaly Kuznetsov
2020-05-25 15:34     ` Kirill A. Shutemov
2020-06-03  1:34       ` Huang, Kai
2020-05-22 12:52 ` [RFC 10/16] KVM: x86: Enabled protected " Kirill A. Shutemov
2020-05-25 15:26   ` Vitaly Kuznetsov
2020-05-26  6:16   ` Mike Rapoport
2020-05-26 21:58     ` Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 11/16] KVM: Rework copy_to/from_guest() to avoid direct mapping Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 12/16] x86/kvm: Share steal time page with host Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 13/16] x86/kvmclock: Share hvclock memory with the host Kirill A. Shutemov
2020-05-25 15:22   ` Vitaly Kuznetsov
2020-05-25 15:25     ` Kirill A. Shutemov
2020-05-25 15:42       ` Vitaly Kuznetsov
2020-05-22 12:52 ` [RFC 14/16] KVM: Introduce gfn_to_pfn_memslot_protected() Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 15/16] KVM: Handle protected memory in __kvm_map_gfn()/__kvm_unmap_gfn() Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 16/16] KVM: Unmap protected pages from direct mapping Kirill A. Shutemov
2020-05-26  6:16   ` Mike Rapoport
2020-05-26 22:10     ` Kirill A. Shutemov
2020-05-25  5:27 ` [RFC 00/16] KVM protected memory extension Kirill A. Shutemov
2020-05-25 13:47 ` Liran Alon
2020-05-25 14:46   ` Kirill A. Shutemov
2020-05-25 15:56     ` Liran Alon
2020-05-26  6:17   ` Mike Rapoport
2020-05-26 10:16     ` Liran Alon
2020-05-26 11:38       ` Mike Rapoport
2020-05-27 15:45         ` Dave Hansen
2020-05-27 21:22           ` Mike Rapoport
2020-06-04 15:15 ` Marc Zyngier
2020-06-04 15:48   ` Sean Christopherson
2020-06-04 16:27     ` Marc Zyngier
2020-06-04 16:35     ` Will Deacon
2020-06-04 19:09       ` Nakajima, Jun
2020-06-04 21:03         ` Jim Mattson
2020-06-04 23:29           ` Nakajima, Jun

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