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From: Mike Rapoport <rppt@kernel.org>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
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>,
	Liran Alon <liran.alon@oracle.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: [RFCv2 15/16] KVM: Unmap protected pages from direct mapping
Date: Fri, 23 Oct 2020 15:37:12 +0300	[thread overview]
Message-ID: <20201023123712.GC392079@kernel.org> (raw)
In-Reply-To: <20201020061859.18385-16-kirill.shutemov@linux.intel.com>

On Tue, Oct 20, 2020 at 09:18:58AM +0300, Kirill A. Shutemov wrote:
> If the protected memory feature enabled, unmap guest memory from
> kernel's direct mappings.
> 
> Migration and KSM is disabled for protected memory as it would require a
> special treatment.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
>  include/linux/mm.h       |  3 +++
>  mm/huge_memory.c         |  8 ++++++++
>  mm/ksm.c                 |  2 ++
>  mm/memory.c              | 12 ++++++++++++
>  mm/rmap.c                |  4 ++++
>  virt/lib/mem_protected.c | 21 +++++++++++++++++++++
>  6 files changed, 50 insertions(+)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index ee274d27e764..74efc51e63f0 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -671,6 +671,9 @@ static inline bool vma_is_kvm_protected(struct vm_area_struct *vma)
>  	return vma->vm_flags & VM_KVM_PROTECTED;
>  }
>  
> +void kvm_map_page(struct page *page, int nr_pages);
> +void kvm_unmap_page(struct page *page, int nr_pages);

This still does not seem right ;-)

And I still think that map/unmap primitives shoud be a part of the
generic mm rather than exported by KVM.

> +
>  #ifdef CONFIG_SHMEM
>  /*
>   * The vma_is_shmem is not inline because it is used only by slow
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index ec8cf9a40cfd..40974656cb43 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -627,6 +627,10 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
>  		spin_unlock(vmf->ptl);
>  		count_vm_event(THP_FAULT_ALLOC);
>  		count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC);
> +
> +		/* Unmap page from direct mapping */
> +		if (vma_is_kvm_protected(vma))
> +			kvm_unmap_page(page, HPAGE_PMD_NR);
>  	}
>  
>  	return 0;
> @@ -1689,6 +1693,10 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
>  			page_remove_rmap(page, true);
>  			VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
>  			VM_BUG_ON_PAGE(!PageHead(page), page);
> +
> +			/* Map the page back to the direct mapping */
> +			if (vma_is_kvm_protected(vma))
> +				kvm_map_page(page, HPAGE_PMD_NR);
>  		} else if (thp_migration_supported()) {
>  			swp_entry_t entry;
>  
> diff --git a/mm/ksm.c b/mm/ksm.c
> index 9afccc36dbd2..c720e271448f 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -528,6 +528,8 @@ static struct vm_area_struct *find_mergeable_vma(struct mm_struct *mm,
>  		return NULL;
>  	if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
>  		return NULL;
> +	if (vma_is_kvm_protected(vma))
> +		return NULL;
>  	return vma;
>  }
>  
> diff --git a/mm/memory.c b/mm/memory.c
> index 2c9756b4e52f..e28bd5f902a7 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -1245,6 +1245,11 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
>  				    likely(!(vma->vm_flags & VM_SEQ_READ)))
>  					mark_page_accessed(page);
>  			}
> +
> +			/* Map the page back to the direct mapping */
> +			if (vma_is_anonymous(vma) && vma_is_kvm_protected(vma))
> +				kvm_map_page(page, 1);
> +
>  			rss[mm_counter(page)]--;
>  			page_remove_rmap(page, false);
>  			if (unlikely(page_mapcount(page) < 0))
> @@ -3466,6 +3471,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
>  	struct page *page;
>  	vm_fault_t ret = 0;
>  	pte_t entry;
> +	bool set = false;
>  
>  	/* File mapping without ->vm_ops ? */
>  	if (vma->vm_flags & VM_SHARED)
> @@ -3554,6 +3560,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
>  	inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
>  	page_add_new_anon_rmap(page, vma, vmf->address, false);
>  	lru_cache_add_inactive_or_unevictable(page, vma);
> +	set = true;
>  setpte:
>  	set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry);
>  
> @@ -3561,6 +3568,11 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
>  	update_mmu_cache(vma, vmf->address, vmf->pte);
>  unlock:
>  	pte_unmap_unlock(vmf->pte, vmf->ptl);
> +
> +	/* Unmap page from direct mapping */
> +	if (vma_is_kvm_protected(vma) && set)
> +		kvm_unmap_page(page, 1);
> +
>  	return ret;
>  release:
>  	put_page(page);
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 9425260774a1..247548d6d24b 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1725,6 +1725,10 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
>  
>  static bool invalid_migration_vma(struct vm_area_struct *vma, void *arg)
>  {
> +	/* TODO */
> +	if (vma_is_kvm_protected(vma))
> +		return true;
> +
>  	return vma_is_temporary_stack(vma);
>  }
>  
> diff --git a/virt/lib/mem_protected.c b/virt/lib/mem_protected.c
> index 1dfe82534242..9d2ef99285e5 100644
> --- a/virt/lib/mem_protected.c
> +++ b/virt/lib/mem_protected.c
> @@ -30,6 +30,27 @@ void kvm_unmap_page_atomic(void *vaddr)
>  }
>  EXPORT_SYMBOL_GPL(kvm_unmap_page_atomic);
>  
> +void kvm_map_page(struct page *page, int nr_pages)
> +{
> +	int i;
> +
> +	/* Clear page before returning it to the direct mapping */
> +	for (i = 0; i < nr_pages; i++) {
> +		void *p = kvm_map_page_atomic(page + i);
> +		memset(p, 0, PAGE_SIZE);
> +		kvm_unmap_page_atomic(p);
> +	}
> +
> +	kernel_map_pages(page, nr_pages, 1);
> +}
> +EXPORT_SYMBOL_GPL(kvm_map_page);
> +
> +void kvm_unmap_page(struct page *page, int nr_pages)
> +{
> +	kernel_map_pages(page, nr_pages, 0);
> +}
> +EXPORT_SYMBOL_GPL(kvm_unmap_page);
> +
>  int kvm_init_protected_memory(void)
>  {
>  	guest_map_ptes = kmalloc_array(num_possible_cpus(),
> -- 
> 2.26.2
> 
> 

-- 
Sincerely yours,
Mike.


  parent reply	other threads:[~2020-10-23 12:37 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
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 [this message]
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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