summaryrefslogtreecommitdiff
path: root/virt
diff options
context:
space:
mode:
authorChao Peng <chao.p.peng@linux.intel.com>2023-10-27 21:21:45 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2023-11-13 13:28:53 +0300
commit8569992d64b8f750e34b7858eac5d7daaf0f80fd (patch)
treed1a199d1f7f70e9cdf08e93b9a151113be35a1e8 /virt
parentc0db19232c1ed6bd7fcb825c28b014c52732c19e (diff)
downloadlinux-8569992d64b8f750e34b7858eac5d7daaf0f80fd.tar.xz
KVM: Use gfn instead of hva for mmu_notifier_retry
Currently in mmu_notifier invalidate path, hva range is recorded and then checked against by mmu_invalidate_retry_hva() in the page fault handling path. However, for the soon-to-be-introduced private memory, a page fault may not have a hva associated, checking gfn(gpa) makes more sense. For existing hva based shared memory, gfn is expected to also work. The only downside is when aliasing multiple gfns to a single hva, the current algorithm of checking multiple ranges could result in a much larger range being rejected. Such aliasing should be uncommon, so the impact is expected small. Suggested-by: Sean Christopherson <seanjc@google.com> Cc: Xu Yilun <yilun.xu@intel.com> Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> Reviewed-by: Fuad Tabba <tabba@google.com> Tested-by: Fuad Tabba <tabba@google.com> [sean: convert vmx_set_apic_access_page_addr() to gfn-based API] Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Xu Yilun <yilun.xu@linux.intel.com> Message-Id: <20231027182217.3615211-4-seanjc@google.com> Reviewed-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c43
1 files changed, 34 insertions, 9 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5a97e6c7d9c2..9cc57b23ec81 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -543,9 +543,7 @@ static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range);
-typedef void (*on_lock_fn_t)(struct kvm *kvm, unsigned long start,
- unsigned long end);
-
+typedef void (*on_lock_fn_t)(struct kvm *kvm);
typedef void (*on_unlock_fn_t)(struct kvm *kvm);
struct kvm_mmu_notifier_range {
@@ -637,7 +635,8 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm,
locked = true;
KVM_MMU_LOCK(kvm);
if (!IS_KVM_NULL_FN(range->on_lock))
- range->on_lock(kvm, range->start, range->end);
+ range->on_lock(kvm);
+
if (IS_KVM_NULL_FN(range->handler))
break;
}
@@ -742,16 +741,29 @@ static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,
kvm_handle_hva_range(mn, address, address + 1, arg, kvm_change_spte_gfn);
}
-void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start,
- unsigned long end)
+void kvm_mmu_invalidate_begin(struct kvm *kvm)
{
+ lockdep_assert_held_write(&kvm->mmu_lock);
/*
* The count increase must become visible at unlock time as no
* spte can be established without taking the mmu_lock and
* count is also read inside the mmu_lock critical section.
*/
kvm->mmu_invalidate_in_progress++;
+
if (likely(kvm->mmu_invalidate_in_progress == 1)) {
+ kvm->mmu_invalidate_range_start = INVALID_GPA;
+ kvm->mmu_invalidate_range_end = INVALID_GPA;
+ }
+}
+
+void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end)
+{
+ lockdep_assert_held_write(&kvm->mmu_lock);
+
+ WARN_ON_ONCE(!kvm->mmu_invalidate_in_progress);
+
+ if (likely(kvm->mmu_invalidate_range_start == INVALID_GPA)) {
kvm->mmu_invalidate_range_start = start;
kvm->mmu_invalidate_range_end = end;
} else {
@@ -771,6 +783,12 @@ void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start,
}
}
+static bool kvm_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+ kvm_mmu_invalidate_range_add(kvm, range->start, range->end);
+ return kvm_unmap_gfn_range(kvm, range);
+}
+
static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
const struct mmu_notifier_range *range)
{
@@ -778,7 +796,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
const struct kvm_mmu_notifier_range hva_range = {
.start = range->start,
.end = range->end,
- .handler = kvm_unmap_gfn_range,
+ .handler = kvm_mmu_unmap_gfn_range,
.on_lock = kvm_mmu_invalidate_begin,
.on_unlock = kvm_arch_guest_memory_reclaimed,
.flush_on_ret = true,
@@ -817,9 +835,10 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
return 0;
}
-void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start,
- unsigned long end)
+void kvm_mmu_invalidate_end(struct kvm *kvm)
{
+ lockdep_assert_held_write(&kvm->mmu_lock);
+
/*
* This sequence increase will notify the kvm page fault that
* the page that is going to be mapped in the spte could have
@@ -834,6 +853,12 @@ void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start,
*/
kvm->mmu_invalidate_in_progress--;
KVM_BUG_ON(kvm->mmu_invalidate_in_progress < 0, kvm);
+
+ /*
+ * Assert that at least one range was added between start() and end().
+ * Not adding a range isn't fatal, but it is a KVM bug.
+ */
+ WARN_ON_ONCE(kvm->mmu_invalidate_range_start == INVALID_GPA);
}
static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,