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Revert "KVM: MMU: fast invalidate all pages" 

Remove x86 KVM's fast invalidate mechanism, i.e. revert all patches
from the original series[1], now that all users of the fast invalidate
mechanism are gone.

This reverts commit 5304b8d37c.

[1] https://lkml.kernel.org/r/1369960590-14138-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com

Cc: Xiao Guangrong <guangrong.xiao@gmail.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2019-02-05 13:01:34 -08:00 committed by Paolo Bonzini
parent 5d6317ca4e
commit ea145aacf4
3 changed files with 1 additions and 100 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/include/asm/kvm_host.h
View File

@ -334,7 +334,6 @@ struct kvm_mmu_page {
int root_count; /* Currently serving as active root */
unsigned int unsync_children;
struct kvm_rmap_head parent_ptes; /* rmap pointers to parent sptes */
unsigned long mmu_valid_gen;
DECLARE_BITMAP(unsync_child_bitmap, 512);
#ifdef CONFIG_X86_32
@ -845,7 +844,6 @@ struct kvm_arch {
unsigned int n_requested_mmu_pages;
unsigned int n_max_mmu_pages;
unsigned int indirect_shadow_pages;
unsigned long mmu_valid_gen;
struct hlist_head mmu_page_hash[KVM_NUM_MMU_PAGES];
/*
* Hash table of struct kvm_mmu_page.

98
arch/x86/kvm/mmu.c
View File

@ -2060,12 +2060,6 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct
if (!direct)
sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
/*
* The active_mmu_pages list is the FIFO list, do not move the
* page until it is zapped. kvm_zap_obsolete_pages depends on
* this feature. See the comments in kvm_zap_obsolete_pages().
*/
list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
kvm_mod_used_mmu_pages(vcpu->kvm, +1);
return sp;
@ -2214,7 +2208,7 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm,
#define for_each_valid_sp(_kvm, _sp, _gfn) \
hlist_for_each_entry(_sp, \
&(_kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(_gfn)], hash_link) \
if (is_obsolete_sp((_kvm), (_sp)) || (_sp)->role.invalid) { \
if ((_sp)->role.invalid) { \
} else
#define for_each_gfn_indirect_valid_sp(_kvm, _sp, _gfn) \
@ -2266,11 +2260,6 @@ static void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) { }
static void mmu_audit_disable(void) { }
#endif
static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
{
return unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen);
}
static bool kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
struct list_head *invalid_list)
{
@ -2495,7 +2484,6 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
if (level > PT_PAGE_TABLE_LEVEL && need_sync)
flush |= kvm_sync_pages(vcpu, gfn, &invalid_list);
}
sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen;
clear_page(sp->spt);
trace_kvm_mmu_get_page(sp, true);
@ -4206,14 +4194,6 @@ static bool fast_cr3_switch(struct kvm_vcpu *vcpu, gpa_t new_cr3,
return false;
if (cached_root_available(vcpu, new_cr3, new_role)) {
/*
* It is possible that the cached previous root page is
* obsolete because of a change in the MMU
* generation number. However, that is accompanied by
* KVM_REQ_MMU_RELOAD, which will free the root that we
* have set here and allocate a new one.
*/
kvm_make_request(KVM_REQ_LOAD_CR3, vcpu);
if (!skip_tlb_flush) {
kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
@ -5865,82 +5845,6 @@ restart:
spin_unlock(&kvm->mmu_lock);
}
static void kvm_zap_obsolete_pages(struct kvm *kvm)
{
struct kvm_mmu_page *sp, *node;
LIST_HEAD(invalid_list);
restart:
list_for_each_entry_safe_reverse(sp, node,
&kvm->arch.active_mmu_pages, link) {
/*
* No obsolete page exists before new created page since
* active_mmu_pages is the FIFO list.
*/
if (!is_obsolete_sp(kvm, sp))
break;
/*
* Do not repeatedly zap a root page to avoid unnecessary
* KVM_REQ_MMU_RELOAD, otherwise we may not be able to
* progress:
* vcpu 0 vcpu 1
* call vcpu_enter_guest():
* 1): handle KVM_REQ_MMU_RELOAD
* and require mmu-lock to
* load mmu
* repeat:
* 1): zap root page and
* send KVM_REQ_MMU_RELOAD
*
* 2): if (cond_resched_lock(mmu-lock))
*
* 2): hold mmu-lock and load mmu
*
* 3): see KVM_REQ_MMU_RELOAD bit
* on vcpu->requests is set
* then return 1 to call
* vcpu_enter_guest() again.
* goto repeat;
*
* Since we are reversely walking the list and the invalid
* list will be moved to the head, skip the invalid page
* can help us to avoid the infinity list walking.
*/
if (sp->role.invalid)
continue;
if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
kvm_mmu_commit_zap_page(kvm, &invalid_list);
cond_resched_lock(&kvm->mmu_lock);
goto restart;
}
if (kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list))
goto restart;
}
kvm_mmu_commit_zap_page(kvm, &invalid_list);
}
/*
* Fast invalidate all shadow pages and use lock-break technique
* to zap obsolete pages.
*
* It's required when memslot is being deleted or VM is being
* destroyed, in these cases, we should ensure that KVM MMU does
* not use any resource of the being-deleted slot or all slots
* after calling the function.
*/
void kvm_mmu_invalidate_zap_all_pages(struct kvm *kvm)
{
spin_lock(&kvm->mmu_lock);
kvm->arch.mmu_valid_gen++;
kvm_zap_obsolete_pages(kvm);
spin_unlock(&kvm->mmu_lock);
}
static void kvm_mmu_zap_mmio_sptes(struct kvm *kvm)
{
struct kvm_mmu_page *sp, *node;

1
arch/x86/kvm/mmu.h
View File

@ -203,7 +203,6 @@ static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
return -(u32)fault & errcode;
}
void kvm_mmu_invalidate_zap_all_pages(struct kvm *kvm);
void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end);
void kvm_mmu_gfn_disallow_lpage(struct kvm_memory_slot *slot, gfn_t gfn);