From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc: "peterz@infradead.org" <peterz@infradead.org>,
"jmattson@google.com" <jmattson@google.com>,
"Christopherson, Sean J" <sean.j.christopherson@intel.com>,
"vkuznets@redhat.com" <vkuznets@redhat.com>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"luto@kernel.org" <luto@kernel.org>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"wanpengli@tencent.com" <wanpengli@tencent.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>,
"keescook@chromium.org" <keescook@chromium.org>,
"rppt@kernel.org" <rppt@kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"x86@kernel.org" <x86@kernel.org>,
"aarcange@redhat.com" <aarcange@redhat.com>,
"liran.alon@oracle.com" <liran.alon@oracle.com>,
"wad@chromium.org" <wad@chromium.org>,
"rientjes@google.com" <rientjes@google.com>,
"Kleen, Andi" <andi.kleen@intel.com>
Subject: Re: [RFCv2 14/16] KVM: Handle protected memory in __kvm_map_gfn()/__kvm_unmap_gfn()
Date: Thu, 22 Oct 2020 15:06:45 +0300 [thread overview]
Message-ID: <20201022120645.vdmytvcmdoku73os@box> (raw)
In-Reply-To: <8404a8802dbdbf81c8f75249039580f9e6942095.camel@intel.com>
On Wed, Oct 21, 2020 at 06:50:28PM +0000, Edgecombe, Rick P wrote:
> On Tue, 2020-10-20 at 09:18 +0300, Kirill A. Shutemov wrote:
> > @@ -467,7 +477,7 @@ void iounmap(volatile void __iomem *addr)
> > p = find_vm_area((void __force *)addr);
> >
> > if (!p) {
> > - printk(KERN_ERR "iounmap: bad address %p\n", addr);
> > + printk(KERN_ERR "iounmap: bad address %px\n", addr);
>
> Unintentional?
Yep. Will fix.
> > @@ -2162,15 +2178,20 @@ static int __kvm_map_gfn(struct kvm_memslots
> > *slots, gfn_t gfn,
> > kvm_cache_gfn_to_pfn(slot, gfn, cache, gen);
> > }
> > pfn = cache->pfn;
> > + protected = cache->protected;
> > } else {
> > if (atomic)
> > return -EAGAIN;
> > - pfn = gfn_to_pfn_memslot(slot, gfn);
> > + pfn = gfn_to_pfn_memslot_protected(slot, gfn,
> > &protected);
> > }
> > if (is_error_noslot_pfn(pfn))
> > return -EINVAL;
> >
> > - if (pfn_valid(pfn)) {
> > + if (protected) {
> > + if (atomic)
> > + return -EAGAIN;
> > + hva = ioremap_cache_force(pfn_to_hpa(pfn), PAGE_SIZE);
> > + } else if (pfn_valid(pfn)) {
> > page = pfn_to_page(pfn);
> > if (atomic)
> > hva = kmap_atomic(page);
>
> I think the page could have got unmapped since the gup via the
> hypercall on another CPU. It could be an avenue for the guest to crash
> the host.
Hm.. I'm not sure I follow. Could you elaborate on what scenario you have
in mind?
--
Kirill A. Shutemov
next prev parent reply other threads:[~2020-10-22 12:06 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-20 6:18 [RFCv2 00/16] KVM protected memory extension Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 01/16] x86/mm: Move force_dma_unencrypted() to common code Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 02/16] x86/kvm: Introduce KVM memory protection feature Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 03/16] x86/kvm: Make DMA pages shared Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 04/16] x86/kvm: Use bounce buffers for KVM memory protection Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 05/16] x86/kvm: Make VirtIO use DMA API in KVM guest Kirill A. Shutemov
2020-10-20 8:06 ` Christoph Hellwig
2020-10-20 12:47 ` Kirill A. Shutemov
2020-10-22 3:31 ` Halil Pasic
2020-10-20 6:18 ` [RFCv2 06/16] x86/kvmclock: Share hvclock memory with the host Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 07/16] x86/realmode: Share trampoline area if KVM memory protection enabled Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 08/16] KVM: Use GUP instead of copy_from/to_user() to access guest memory Kirill A. Shutemov
2020-10-20 8:25 ` John Hubbard
2020-10-20 12:51 ` Kirill A. Shutemov
2020-10-22 11:49 ` Matthew Wilcox
2020-10-22 19:58 ` John Hubbard
2020-10-26 4:21 ` Matthew Wilcox
2020-10-26 4:44 ` John Hubbard
2020-10-26 13:28 ` Matthew Wilcox
2020-10-26 14:16 ` Jason Gunthorpe
2020-10-26 20:52 ` John Hubbard
2020-10-20 17:29 ` Ira Weiny
2020-10-22 11:37 ` Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 09/16] KVM: mm: Introduce VM_KVM_PROTECTED Kirill A. Shutemov
2020-10-21 18:47 ` Edgecombe, Rick P
2020-10-22 12:01 ` Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 10/16] KVM: x86: Use GUP for page walk instead of __get_user() Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 11/16] KVM: Protected memory extension Kirill A. Shutemov
2020-10-20 7:17 ` Peter Zijlstra
2020-10-20 12:55 ` Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 12/16] KVM: x86: Enabled protected " Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 13/16] KVM: Rework copy_to/from_guest() to avoid direct mapping Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 14/16] KVM: Handle protected memory in __kvm_map_gfn()/__kvm_unmap_gfn() Kirill A. Shutemov
2020-10-21 18:50 ` Edgecombe, Rick P
2020-10-22 12:06 ` Kirill A. Shutemov [this message]
2020-10-22 16:59 ` Edgecombe, Rick P
2020-10-23 10:36 ` Kirill A. Shutemov
2020-10-22 3:26 ` Halil Pasic
2020-10-22 12:07 ` Kirill A. Shutemov
2020-10-20 6:18 ` [RFCv2 15/16] KVM: Unmap protected pages from direct mapping Kirill A. Shutemov
2020-10-20 7:12 ` Peter Zijlstra
2020-10-20 12:18 ` David Hildenbrand
2020-10-20 13:20 ` David Hildenbrand
2020-10-21 1:20 ` Edgecombe, Rick P
2020-10-26 19:55 ` Tom Lendacky
2020-10-21 18:49 ` Edgecombe, Rick P
2020-10-23 12:37 ` Mike Rapoport
2020-10-23 16:32 ` Sean Christopherson
2020-10-20 6:18 ` [RFCv2 16/16] mm: Do not use zero page for VM_KVM_PROTECTED VMAs Kirill A. Shutemov
2020-10-20 7:46 ` [RFCv2 00/16] KVM protected memory extension Vitaly Kuznetsov
2020-10-20 13:49 ` Kirill A. Shutemov
2020-10-21 14:46 ` Vitaly Kuznetsov
2020-10-23 11:35 ` Kirill A. Shutemov
2020-10-23 12:01 ` Vitaly Kuznetsov
2020-10-21 18:20 ` Andy Lutomirski
2020-10-26 15:29 ` Kirill A. Shutemov
2020-10-26 23:58 ` Andy Lutomirski
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