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From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: 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>
Cc: 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>,
	Mike Rapoport  <rppt@kernel.org>,
	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: [RFCv2 11/16] KVM: Protected memory extension
Date: Tue, 20 Oct 2020 09:18:54 +0300	[thread overview]
Message-ID: <20201020061859.18385-12-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20201020061859.18385-1-kirill.shutemov@linux.intel.com>

Add infrastructure that handles protected memory extension.

Arch-specific code has to provide hypercalls and define non-zero
VM_KVM_PROTECTED.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/kvm_host.h |  4 +++
 virt/kvm/Kconfig         |  3 ++
 virt/kvm/kvm_main.c      | 68 ++++++++++++++++++++++++++++++++++++++
 virt/lib/Makefile        |  1 +
 virt/lib/mem_protected.c | 71 ++++++++++++++++++++++++++++++++++++++++
 5 files changed, 147 insertions(+)
 create mode 100644 virt/lib/mem_protected.c

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 380a64613880..6655e8da4555 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -701,6 +701,10 @@ void kvm_arch_flush_shadow_all(struct kvm *kvm);
 void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
 				   struct kvm_memory_slot *slot);
 
+int kvm_protect_all_memory(struct kvm *kvm);
+int kvm_protect_memory(struct kvm *kvm,
+		       unsigned long gfn, unsigned long npages, bool protect);
+
 int gfn_to_page_many_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
 			    struct page **pages, int nr_pages);
 
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 1c37ccd5d402..50d7422386aa 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -63,3 +63,6 @@ config HAVE_KVM_NO_POLL
 
 config KVM_XFER_TO_GUEST_WORK
        bool
+
+config HAVE_KVM_PROTECTED_MEMORY
+       bool
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 125db5a73e10..4c008c7b4974 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -154,6 +154,8 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
 static unsigned long long kvm_createvm_count;
 static unsigned long long kvm_active_vms;
 
+int __kvm_protect_memory(unsigned long start, unsigned long end, bool protect);
+
 __weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
 						   unsigned long start, unsigned long end)
 {
@@ -1371,6 +1373,15 @@ int __kvm_set_memory_region(struct kvm *kvm,
 	if (r)
 		goto out_bitmap;
 
+	if (IS_ENABLED(CONFIG_HAVE_KVM_PROTECTED_MEMORY) &&
+	    mem->memory_size && kvm->mem_protected) {
+		r = __kvm_protect_memory(new.userspace_addr,
+					 new.userspace_addr + new.npages * PAGE_SIZE,
+					 true);
+		if (r)
+			goto out_bitmap;
+	}
+
 	if (old.dirty_bitmap && !new.dirty_bitmap)
 		kvm_destroy_dirty_bitmap(&old);
 	return 0;
@@ -2720,6 +2731,63 @@ void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn)
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_mark_page_dirty);
 
+int kvm_protect_memory(struct kvm *kvm,
+		       unsigned long gfn, unsigned long npages, bool protect)
+{
+	struct kvm_memory_slot *memslot;
+	unsigned long start, end;
+	gfn_t numpages;
+
+	if (!IS_ENABLED(CONFIG_HAVE_KVM_PROTECTED_MEMORY))
+		return -KVM_ENOSYS;
+
+	if (!npages)
+		return 0;
+
+	memslot = gfn_to_memslot(kvm, gfn);
+	/* Not backed by memory. It's okay. */
+	if (!memslot)
+		return 0;
+
+	start = gfn_to_hva_many(memslot, gfn, &numpages);
+	end = start + npages * PAGE_SIZE;
+
+	/* XXX: Share range across memory slots? */
+	if (WARN_ON(numpages < npages))
+		return -EINVAL;
+
+	return __kvm_protect_memory(start, end, protect);
+}
+EXPORT_SYMBOL_GPL(kvm_protect_memory);
+
+int kvm_protect_all_memory(struct kvm *kvm)
+{
+	struct kvm_memslots *slots;
+	struct kvm_memory_slot *memslot;
+	unsigned long start, end;
+	int i, ret = 0;;
+
+	if (!IS_ENABLED(CONFIG_HAVE_KVM_PROTECTED_MEMORY))
+		return -KVM_ENOSYS;
+
+	mutex_lock(&kvm->slots_lock);
+	kvm->mem_protected = true;
+	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+		slots = __kvm_memslots(kvm, i);
+		kvm_for_each_memslot(memslot, slots) {
+			start = memslot->userspace_addr;
+			end = start + memslot->npages * PAGE_SIZE;
+			ret = __kvm_protect_memory(start, end, true);
+			if (ret)
+				goto out;
+		}
+	}
+out:
+	mutex_unlock(&kvm->slots_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kvm_protect_all_memory);
+
 void kvm_sigset_activate(struct kvm_vcpu *vcpu)
 {
 	if (!vcpu->sigset_active)
diff --git a/virt/lib/Makefile b/virt/lib/Makefile
index bd7f9a78bb6b..d6e50510801f 100644
--- a/virt/lib/Makefile
+++ b/virt/lib/Makefile
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_IRQ_BYPASS_MANAGER) += irqbypass.o
+obj-$(CONFIG_HAVE_KVM_PROTECTED_MEMORY) += mem_protected.o
diff --git a/virt/lib/mem_protected.c b/virt/lib/mem_protected.c
new file mode 100644
index 000000000000..0b01dd74f29c
--- /dev/null
+++ b/virt/lib/mem_protected.c
@@ -0,0 +1,71 @@
+#include <linux/kvm_host.h>
+#include <linux/mm.h>
+#include <linux/pagewalk.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <asm/tlbflush.h>
+
+int __kvm_protect_memory(unsigned long start, unsigned long end, bool protect)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma, *prev;
+	int ret;
+
+	if (mmap_write_lock_killable(mm))
+		return -EINTR;
+
+	ret = -ENOMEM;
+	vma = find_vma(current->mm, start);
+	if (!vma)
+		goto out;
+
+	ret = -EINVAL;
+	if (vma->vm_start > start)
+		goto out;
+
+	if (start > vma->vm_start)
+		prev = vma;
+	else
+		prev = vma->vm_prev;
+
+	ret = 0;
+	while (true) {
+		unsigned long newflags, tmp;
+
+		tmp = vma->vm_end;
+		if (tmp > end)
+			tmp = end;
+
+		newflags = vma->vm_flags;
+		if (protect)
+			newflags |= VM_KVM_PROTECTED;
+		else
+			newflags &= ~VM_KVM_PROTECTED;
+
+		/* The VMA has been handled as part of other memslot */
+		if (newflags == vma->vm_flags)
+			goto next;
+
+		ret = mprotect_fixup(vma, &prev, start, tmp, newflags);
+		if (ret)
+			goto out;
+
+next:
+		start = tmp;
+		if (start < prev->vm_end)
+			start = prev->vm_end;
+
+		if (start >= end)
+			goto out;
+
+		vma = prev->vm_next;
+		if (!vma || vma->vm_start != start) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	}
+out:
+	mmap_write_unlock(mm);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__kvm_protect_memory);
-- 
2.26.2



  parent reply	other threads:[~2020-10-20  6:19 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-20  6:18 [RFCv2 00/16] KVM protected " 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 ` Kirill A. Shutemov [this message]
2020-10-20  7:17   ` [RFCv2 11/16] KVM: Protected memory extension 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
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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