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>,
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: [RFC 06/16] KVM: Use GUP instead of copy_from/to_user() to access guest memory
Date: Fri, 22 May 2020 15:52:04 +0300 [thread overview]
Message-ID: <20200522125214.31348-7-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20200522125214.31348-1-kirill.shutemov@linux.intel.com>
New helpers copy_from_guest()/copy_to_guest() to be used if KVM memory
protection feature is enabled.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
include/linux/kvm_host.h | 4 +++
virt/kvm/kvm_main.c | 78 ++++++++++++++++++++++++++++++++++------
2 files changed, 72 insertions(+), 10 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 131cc1527d68..bd0bb600f610 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -503,6 +503,7 @@ struct kvm {
struct srcu_struct srcu;
struct srcu_struct irq_srcu;
pid_t userspace_pid;
+ bool mem_protected;
};
#define kvm_err(fmt, ...) \
@@ -727,6 +728,9 @@ void kvm_set_pfn_dirty(kvm_pfn_t pfn);
void kvm_set_pfn_accessed(kvm_pfn_t pfn);
void kvm_get_pfn(kvm_pfn_t pfn);
+int copy_from_guest(void *data, unsigned long hva, int len);
+int copy_to_guest(unsigned long hva, const void *data, int len);
+
void kvm_release_pfn(kvm_pfn_t pfn, bool dirty, struct gfn_to_pfn_cache *cache);
int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
int len);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 731c1e517716..033471f71dae 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2248,8 +2248,48 @@ static int next_segment(unsigned long len, int offset)
return len;
}
+int copy_from_guest(void *data, unsigned long hva, int len)
+{
+ int offset = offset_in_page(hva);
+ struct page *page;
+ int npages, seg;
+
+ while ((seg = next_segment(len, offset)) != 0) {
+ npages = get_user_pages_unlocked(hva, 1, &page, 0);
+ if (npages != 1)
+ return -EFAULT;
+ memcpy(data, page_address(page) + offset, seg);
+ put_page(page);
+ len -= seg;
+ hva += seg;
+ offset = 0;
+ }
+
+ return 0;
+}
+
+int copy_to_guest(unsigned long hva, const void *data, int len)
+{
+ int offset = offset_in_page(hva);
+ struct page *page;
+ int npages, seg;
+
+ while ((seg = next_segment(len, offset)) != 0) {
+ npages = get_user_pages_unlocked(hva, 1, &page, FOLL_WRITE);
+ if (npages != 1)
+ return -EFAULT;
+ memcpy(page_address(page) + offset, data, seg);
+ put_page(page);
+ len -= seg;
+ hva += seg;
+ offset = 0;
+ }
+ return 0;
+}
+
static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn,
- void *data, int offset, int len)
+ void *data, int offset, int len,
+ bool protected)
{
int r;
unsigned long addr;
@@ -2257,7 +2297,10 @@ static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn,
addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
if (kvm_is_error_hva(addr))
return -EFAULT;
- r = __copy_from_user(data, (void __user *)addr + offset, len);
+ if (protected)
+ r = copy_from_guest(data, addr + offset, len);
+ else
+ r = __copy_from_user(data, (void __user *)addr + offset, len);
if (r)
return -EFAULT;
return 0;
@@ -2268,7 +2311,8 @@ int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
{
struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
- return __kvm_read_guest_page(slot, gfn, data, offset, len);
+ return __kvm_read_guest_page(slot, gfn, data, offset, len,
+ kvm->mem_protected);
}
EXPORT_SYMBOL_GPL(kvm_read_guest_page);
@@ -2277,7 +2321,8 @@ int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data,
{
struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
- return __kvm_read_guest_page(slot, gfn, data, offset, len);
+ return __kvm_read_guest_page(slot, gfn, data, offset, len,
+ vcpu->kvm->mem_protected);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_page);
@@ -2350,7 +2395,8 @@ int kvm_vcpu_read_guest_atomic(struct kvm_vcpu *vcpu, gpa_t gpa,
EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_atomic);
static int __kvm_write_guest_page(struct kvm_memory_slot *memslot, gfn_t gfn,
- const void *data, int offset, int len)
+ const void *data, int offset, int len,
+ bool protected)
{
int r;
unsigned long addr;
@@ -2358,7 +2404,11 @@ static int __kvm_write_guest_page(struct kvm_memory_slot *memslot, gfn_t gfn,
addr = gfn_to_hva_memslot(memslot, gfn);
if (kvm_is_error_hva(addr))
return -EFAULT;
- r = __copy_to_user((void __user *)addr + offset, data, len);
+
+ if (protected)
+ r = copy_to_guest(addr + offset, data, len);
+ else
+ r = __copy_to_user((void __user *)addr + offset, data, len);
if (r)
return -EFAULT;
mark_page_dirty_in_slot(memslot, gfn);
@@ -2370,7 +2420,8 @@ int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn,
{
struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
- return __kvm_write_guest_page(slot, gfn, data, offset, len);
+ return __kvm_write_guest_page(slot, gfn, data, offset, len,
+ kvm->mem_protected);
}
EXPORT_SYMBOL_GPL(kvm_write_guest_page);
@@ -2379,7 +2430,8 @@ int kvm_vcpu_write_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn,
{
struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
- return __kvm_write_guest_page(slot, gfn, data, offset, len);
+ return __kvm_write_guest_page(slot, gfn, data, offset, len,
+ vcpu->kvm->mem_protected);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest_page);
@@ -2495,7 +2547,10 @@ int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
if (unlikely(!ghc->memslot))
return kvm_write_guest(kvm, gpa, data, len);
- r = __copy_to_user((void __user *)ghc->hva + offset, data, len);
+ if (kvm->mem_protected)
+ r = copy_to_guest(ghc->hva + offset, data, len);
+ else
+ r = __copy_to_user((void __user *)ghc->hva + offset, data, len);
if (r)
return -EFAULT;
mark_page_dirty_in_slot(ghc->memslot, gpa >> PAGE_SHIFT);
@@ -2530,7 +2585,10 @@ int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
if (unlikely(!ghc->memslot))
return kvm_read_guest(kvm, ghc->gpa, data, len);
- r = __copy_from_user(data, (void __user *)ghc->hva, len);
+ if (kvm->mem_protected)
+ r = copy_from_guest(data, ghc->hva, len);
+ else
+ r = __copy_from_user(data, (void __user *)ghc->hva, len);
if (r)
return -EFAULT;
--
2.26.2
next prev parent reply other threads:[~2020-05-22 12:53 UTC|newest]
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 ` Kirill A. Shutemov [this message]
2020-05-25 15:08 ` [RFC 06/16] KVM: Use GUP instead of copy_from/to_user() to access guest memory 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
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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