On 04.11.2021 01:25, Sean Christopherson wrote:
From: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx>
There is no point in recalculating from scratch the total number of pages
in all memslots each time a memslot is created or deleted. Use KVM's
cached nr_memslot_pages to compute the default max number of MMU pages.
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx>
[sean: use common KVM field and rework changelog accordingly]
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 1 -
arch/x86/kvm/mmu/mmu.c | 24 ------------------------
arch/x86/kvm/x86.c | 11 ++++++++---
3 files changed, 8 insertions(+), 28 deletions(-)
(..)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11837,9 +11837,14 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
enum kvm_mr_change change)
{
if (!kvm->arch.n_requested_mmu_pages &&
- (change == KVM_MR_CREATE || change == KVM_MR_DELETE))
- kvm_mmu_change_mmu_pages(kvm,
- kvm_mmu_calculate_default_mmu_pages(kvm));
+ (change == KVM_MR_CREATE || change == KVM_MR_DELETE)) {
+ unsigned long nr_mmu_pages;
+
+ nr_mmu_pages = kvm->nr_memslot_pages * KVM_PERMILLE_MMU_PAGES;
Unfortunately, even if kvm->nr_memslot_pages is capped at ULONG_MAX then
this value multiplied by 20 can still overflow an unsigned long variable.
Thanks,
Maciej
