From: Nikunj A Dadhania <nikunj@amd.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Brijesh Singh <brijesh.singh@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Peter Gonda <pgonda@google.com>, Bharata B Rao <bharata@amd.com>,
"Maciej S . Szmigiero" <mail@maciej.szmigiero.name>,
Mingwei Zhang <mizhang@google.com>,
"David Hildenbrand" <david@redhat.com>, <kvm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
Nikunj A Dadhania <nikunj@amd.com>
Subject: [PATCH RFC v1 1/9] KVM: Introduce pinning flag to hva_to_pfn*
Date: Tue, 8 Mar 2022 10:08:49 +0530 [thread overview]
Message-ID: <20220308043857.13652-2-nikunj@amd.com> (raw)
In-Reply-To: <20220308043857.13652-1-nikunj@amd.com>
KVM allocates pages with get_user_pages_* (that use FOLL_GET). For
long term pinning of guest pages pin_user_pages_* (that use FOLL_PIN)
need to be used. Add a flag to hva_to_pfn* to allocate pinned pages
when the memslot represents encrypted memory.
Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
include/linux/kvm_host.h | 6 ++++
virt/kvm/kvm_main.c | 63 ++++++++++++++++++++++++++++++----------
virt/kvm/kvm_mm.h | 2 +-
virt/kvm/pfncache.c | 2 +-
4 files changed, 56 insertions(+), 17 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index f11039944c08..c23022960d51 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -55,6 +55,7 @@
* include/linux/kvm_h.
*/
#define KVM_MEMSLOT_INVALID (1UL << 16)
+#define KVM_MEMSLOT_ENCRYPTED (1UL << 17)
/*
* Bit 63 of the memslot generation number is an "update in-progress flag",
@@ -583,6 +584,11 @@ static inline unsigned long *kvm_second_dirty_bitmap(struct kvm_memory_slot *mem
return memslot->dirty_bitmap + len / sizeof(*memslot->dirty_bitmap);
}
+static inline bool memslot_is_encrypted(const struct kvm_memory_slot *slot)
+{
+ return slot && (slot->flags & KVM_MEMSLOT_ENCRYPTED);
+}
+
#ifndef KVM_DIRTY_LOG_MANUAL_CAPS
#define KVM_DIRTY_LOG_MANUAL_CAPS KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE
#endif
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0afc016cc54d..c035fe6b39ec 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2381,9 +2381,10 @@ static inline int check_user_page_hwpoison(unsigned long addr)
* only part that runs if we can in atomic context.
*/
static bool hva_to_pfn_fast(unsigned long addr, bool write_fault,
- bool *writable, kvm_pfn_t *pfn)
+ bool *writable, kvm_pfn_t *pfn, bool use_pin)
{
struct page *page[1];
+ bool ret;
/*
* Fast pin a writable pfn only if it is a write fault request
@@ -2393,7 +2394,12 @@ static bool hva_to_pfn_fast(unsigned long addr, bool write_fault,
if (!(write_fault || writable))
return false;
- if (get_user_page_fast_only(addr, FOLL_WRITE, page)) {
+ if (!use_pin)
+ ret = get_user_page_fast_only(addr, FOLL_WRITE, page);
+ else
+ ret = pin_user_pages_fast_only(addr, 1, FOLL_WRITE | FOLL_LONGTERM, page);
+
+ if (ret) {
*pfn = page_to_pfn(page[0]);
if (writable)
@@ -2409,9 +2415,9 @@ static bool hva_to_pfn_fast(unsigned long addr, bool write_fault,
* 1 indicates success, -errno is returned if error is detected.
*/
static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
- bool *writable, kvm_pfn_t *pfn)
+ bool *writable, kvm_pfn_t *pfn, bool use_pin)
{
- unsigned int flags = FOLL_HWPOISON;
+ unsigned int flags = 0;
struct page *page;
int npages = 0;
@@ -2422,20 +2428,41 @@ static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
if (write_fault)
flags |= FOLL_WRITE;
- if (async)
- flags |= FOLL_NOWAIT;
- npages = get_user_pages_unlocked(addr, 1, &page, flags);
+ if (!use_pin) {
+ flags |= FOLL_HWPOISON;
+ if (async)
+ flags |= FOLL_NOWAIT;
+
+ npages = get_user_pages_unlocked(addr, 1, &page, flags);
+ } else {
+ /*
+ * FOLL_LONGTERM is not supported in pin_user_pages_unlocked,
+ * use *_fast instead.
+ */
+ flags |= FOLL_LONGTERM;
+ npages = pin_user_pages_fast(addr, 1, flags, &page);
+ }
+
if (npages != 1)
return npages;
/* map read fault as writable if possible */
if (unlikely(!write_fault) && writable) {
struct page *wpage;
+ bool ret;
+
+ if (!use_pin)
+ ret = get_user_page_fast_only(addr, FOLL_WRITE, &wpage);
+ else
+ ret = pin_user_pages_fast_only(addr, 1, FOLL_WRITE | FOLL_LONGTERM, &wpage);
- if (get_user_page_fast_only(addr, FOLL_WRITE, &wpage)) {
+ if (ret) {
*writable = true;
- put_page(page);
+ if (!use_pin)
+ put_page(page);
+ else
+ unpin_user_page(page);
page = wpage;
}
}
@@ -2541,7 +2568,7 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma,
* whether the mapping is writable.
*/
kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
- bool write_fault, bool *writable)
+ bool write_fault, bool *writable, bool use_pin)
{
struct vm_area_struct *vma;
kvm_pfn_t pfn = 0;
@@ -2550,13 +2577,13 @@ kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
/* we can do it either atomically or asynchronously, not both */
BUG_ON(atomic && async);
- if (hva_to_pfn_fast(addr, write_fault, writable, &pfn))
+ if (hva_to_pfn_fast(addr, write_fault, writable, &pfn, use_pin))
return pfn;
if (atomic)
return KVM_PFN_ERR_FAULT;
- npages = hva_to_pfn_slow(addr, async, write_fault, writable, &pfn);
+ npages = hva_to_pfn_slow(addr, async, write_fault, writable, &pfn, use_pin);
if (npages == 1)
return pfn;
@@ -2616,7 +2643,7 @@ kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn,
}
return hva_to_pfn(addr, atomic, async, write_fault,
- writable);
+ writable, memslot_is_encrypted(slot));
}
EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot);
@@ -2788,8 +2815,14 @@ EXPORT_SYMBOL_GPL(kvm_release_page_clean);
void kvm_release_pfn_clean(kvm_pfn_t pfn)
{
- if (!is_error_noslot_pfn(pfn) && !kvm_is_reserved_pfn(pfn))
- put_page(pfn_to_page(pfn));
+ if (!is_error_noslot_pfn(pfn) && !kvm_is_reserved_pfn(pfn)) {
+ struct page *page = pfn_to_page(pfn);
+
+ if (page_maybe_dma_pinned(page))
+ unpin_user_page(page);
+ else
+ put_page(page);
+ }
}
EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);
diff --git a/virt/kvm/kvm_mm.h b/virt/kvm/kvm_mm.h
index 34ca40823260..b1a5e379949b 100644
--- a/virt/kvm/kvm_mm.h
+++ b/virt/kvm/kvm_mm.h
@@ -25,7 +25,7 @@
#endif /* KVM_HAVE_MMU_RWLOCK */
kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
- bool write_fault, bool *writable);
+ bool write_fault, bool *writable, bool use_pin);
#ifdef CONFIG_HAVE_KVM_PFNCACHE
void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm,
diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c
index ce878f4be4da..44384f06c81b 100644
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -135,7 +135,7 @@ static kvm_pfn_t hva_to_pfn_retry(struct kvm *kvm, unsigned long uhva)
smp_rmb();
/* We always request a writeable mapping */
- new_pfn = hva_to_pfn(uhva, false, NULL, true, NULL);
+ new_pfn = hva_to_pfn(uhva, false, NULL, true, NULL, false);
if (is_error_noslot_pfn(new_pfn))
break;
--
2.32.0
next prev parent reply other threads:[~2022-03-08 4:40 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-08 4:38 [PATCH RFC v1 0/9] KVM: SVM: Defer page pinning for SEV guests Nikunj A Dadhania
2022-03-08 4:38 ` Nikunj A Dadhania [this message]
2022-03-08 4:38 ` [PATCH RFC v1 2/9] KVM: x86/mmu: Move hugepage adjust to direct_page_fault Nikunj A Dadhania
2022-03-28 21:04 ` Sean Christopherson
2022-03-08 4:38 ` [PATCH RFC v1 3/9] KVM: x86/mmu: Add hook to pin PFNs on demand in MMU Nikunj A Dadhania
2022-03-08 4:38 ` [PATCH RFC v1 4/9] KVM: SVM: Add pinning metadata in the arch memslot Nikunj A Dadhania
2022-03-08 4:38 ` [PATCH RFC v1 5/9] KVM: SVM: Implement demand page pinning Nikunj A Dadhania
2022-03-08 21:53 ` Mingwei Zhang
2022-03-09 5:10 ` Nikunj A. Dadhania
2022-03-21 6:11 ` Mingwei Zhang
2022-03-21 9:19 ` Nikunj A. Dadhania
2022-03-08 4:38 ` [PATCH RFC v1 6/9] KVM: x86/mmu: Introduce kvm_mmu_map_tdp_page() for use by SEV/TDX Nikunj A Dadhania
2022-03-08 4:38 ` [PATCH RFC v1 7/9] KVM: SEV: Carve out routine for allocation of pages Nikunj A Dadhania
2022-03-08 4:38 ` [PATCH RFC v1 8/9] KVM: Move kvm_for_each_memslot_in_hva_range() to be used in SVM Nikunj A Dadhania
2022-03-08 4:38 ` [PATCH RFC v1 9/9] KVM: SVM: Pin SEV pages in MMU during sev_launch_update_data() Nikunj A Dadhania
2022-03-09 16:57 ` Maciej S. Szmigiero
2022-03-09 17:47 ` Nikunj A. Dadhania
2022-03-28 21:00 ` [PATCH RFC v1 0/9] KVM: SVM: Defer page pinning for SEV guests Sean Christopherson
2022-03-30 4:42 ` Nikunj A. Dadhania
2022-03-30 19:47 ` Sean Christopherson
2022-03-31 4:48 ` Nikunj A. Dadhania
2022-03-31 18:32 ` Peter Gonda
2022-03-31 19:00 ` Sean Christopherson
2022-04-01 3:22 ` Nikunj A. Dadhania
2022-04-01 14:54 ` Sean Christopherson
2022-04-01 15:39 ` Nikunj A. Dadhania
2022-04-01 17:28 ` Marc Orr
2022-04-01 18:02 ` Sean Christopherson
2022-04-01 18:19 ` Marc Orr
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