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Date: Tue, 5 Apr 2016 14:39:29 -0700 (PDT)
From: Hugh Dickins <hughd@...gle.com>
To: Andrew Morton <akpm@...ux-foundation.org>
cc: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Andrea Arcangeli <aarcange@...hat.com>,
Andres Lagar-Cavilla <andreslc@...gle.com>,
Yang Shi <yang.shi@...aro.org>, Ning Qu <quning@...il.com>,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
linux-mm@...ck.org
Subject: [PATCH 16/31] kvm: plumb return of hva when resolving page fault.
From: Andres Lagar-Cavilla <andreslc@...gle.com>
So we don't have to redo this work later. Note the hva is not racy,
it is simple arithmetic based on the memslot.
This will be used in the huge tmpfs commits.
Signed-off-by: Andres Lagar-Cavilla <andreslc@...gle.com>
Signed-off-by: Hugh Dickins <hughd@...gle.com>
---
Cc'ed to kvm@...r.kernel.org as an FYI: this patch is not expected to
go into the tree in the next few weeks. The context is a huge tmpfs
patchset which implements huge pagecache transparently on tmpfs,
using a team of small pages rather than one compound page:
please refer to linux-mm or linux-kernel for more context.
arch/x86/kvm/mmu.c | 20 ++++++++++++++------
arch/x86/kvm/paging_tmpl.h | 3 ++-
include/linux/kvm_host.h | 2 +-
virt/kvm/kvm_main.c | 14 ++++++++------
4 files changed, 25 insertions(+), 14 deletions(-)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2992,7 +2992,8 @@ exit:
}
static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
- gva_t gva, kvm_pfn_t *pfn, bool write, bool *writable);
+ gva_t gva, kvm_pfn_t *pfn, bool write, bool *writable,
+ unsigned long *hva);
static void make_mmu_pages_available(struct kvm_vcpu *vcpu);
static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
@@ -3003,6 +3004,7 @@ static int nonpaging_map(struct kvm_vcpu
bool force_pt_level = false;
kvm_pfn_t pfn;
unsigned long mmu_seq;
+ unsigned long hva;
bool map_writable, write = error_code & PFERR_WRITE_MASK;
level = mapping_level(vcpu, gfn, &force_pt_level);
@@ -3024,7 +3026,8 @@ static int nonpaging_map(struct kvm_vcpu
mmu_seq = vcpu->kvm->mmu_notifier_seq;
smp_rmb();
- if (try_async_pf(vcpu, prefault, gfn, v, &pfn, write, &map_writable))
+ if (try_async_pf(vcpu, prefault, gfn, v, &pfn, write,
+ &map_writable, &hva))
return 0;
if (handle_abnormal_pfn(vcpu, v, gfn, pfn, ACC_ALL, &r))
@@ -3487,14 +3490,16 @@ static bool can_do_async_pf(struct kvm_v
}
static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
- gva_t gva, kvm_pfn_t *pfn, bool write, bool *writable)
+ gva_t gva, kvm_pfn_t *pfn, bool write, bool *writable,
+ unsigned long *hva)
{
struct kvm_memory_slot *slot;
bool async;
slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
async = false;
- *pfn = __gfn_to_pfn_memslot(slot, gfn, false, &async, write, writable);
+ *pfn = __gfn_to_pfn_memslot(slot, gfn,
+ false, &async, write, writable, hva);
if (!async)
return false; /* *pfn has correct page already */
@@ -3508,7 +3513,8 @@ static bool try_async_pf(struct kvm_vcpu
return true;
}
- *pfn = __gfn_to_pfn_memslot(slot, gfn, false, NULL, write, writable);
+ *pfn = __gfn_to_pfn_memslot(slot, gfn,
+ false, NULL, write, writable, hva);
return false;
}
@@ -3531,6 +3537,7 @@ static int tdp_page_fault(struct kvm_vcp
bool force_pt_level;
gfn_t gfn = gpa >> PAGE_SHIFT;
unsigned long mmu_seq;
+ unsigned long hva;
int write = error_code & PFERR_WRITE_MASK;
bool map_writable;
@@ -3559,7 +3566,8 @@ static int tdp_page_fault(struct kvm_vcp
mmu_seq = vcpu->kvm->mmu_notifier_seq;
smp_rmb();
- if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write, &map_writable))
+ if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write,
+ &map_writable, &hva))
return 0;
if (handle_abnormal_pfn(vcpu, 0, gfn, pfn, ACC_ALL, &r))
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -712,6 +712,7 @@ static int FNAME(page_fault)(struct kvm_
int level = PT_PAGE_TABLE_LEVEL;
bool force_pt_level = false;
unsigned long mmu_seq;
+ unsigned long hva;
bool map_writable, is_self_change_mapping;
pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
@@ -765,7 +766,7 @@ static int FNAME(page_fault)(struct kvm_
smp_rmb();
if (try_async_pf(vcpu, prefault, walker.gfn, addr, &pfn, write_fault,
- &map_writable))
+ &map_writable, &hva))
return 0;
if (handle_abnormal_pfn(vcpu, mmu_is_nested(vcpu) ? 0 : addr,
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -600,7 +600,7 @@ kvm_pfn_t gfn_to_pfn_memslot(struct kvm_
kvm_pfn_t gfn_to_pfn_memslot_atomic(struct kvm_memory_slot *slot, gfn_t gfn);
kvm_pfn_t __gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn,
bool atomic, bool *async, bool write_fault,
- bool *writable);
+ bool *writable, unsigned long *hva);
void kvm_release_pfn_clean(kvm_pfn_t pfn);
void kvm_set_pfn_dirty(kvm_pfn_t pfn);
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1444,7 +1444,7 @@ exit:
kvm_pfn_t __gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn,
bool atomic, bool *async, bool write_fault,
- bool *writable)
+ bool *writable, unsigned long *hva)
{
unsigned long addr = __gfn_to_hva_many(slot, gfn, NULL, write_fault);
@@ -1466,8 +1466,10 @@ kvm_pfn_t __gfn_to_pfn_memslot(struct kv
writable = NULL;
}
- return hva_to_pfn(addr, atomic, async, write_fault,
- writable);
+ if (hva)
+ *hva = addr;
+
+ return hva_to_pfn(addr, atomic, async, write_fault, writable);
}
EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot);
@@ -1475,19 +1477,19 @@ kvm_pfn_t gfn_to_pfn_prot(struct kvm *kv
bool *writable)
{
return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, NULL,
- write_fault, writable);
+ write_fault, writable, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_pfn_prot);
kvm_pfn_t gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn)
{
- return __gfn_to_pfn_memslot(slot, gfn, false, NULL, true, NULL);
+ return __gfn_to_pfn_memslot(slot, gfn, false, NULL, true, NULL, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot);
kvm_pfn_t gfn_to_pfn_memslot_atomic(struct kvm_memory_slot *slot, gfn_t gfn)
{
- return __gfn_to_pfn_memslot(slot, gfn, true, NULL, true, NULL);
+ return __gfn_to_pfn_memslot(slot, gfn, true, NULL, true, NULL, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot_atomic);
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