kvm_mmu_calculate_mmu_pages numbers,
maximum number of shadow pages = 2% of mapped guest pages
Does not make sense for TDP guests where mapping all of guest
memory with 4k pages cannot exceed "mapped guest pages / 512"
(not counting root pages).
Allow that maximum for TDP, forcing the guest to recycle otherwise.
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 956ca35..a9694a8d7 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4293,7 +4293,7 @@ nomem:
unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
{
unsigned int nr_mmu_pages;
- unsigned int nr_pages = 0;
+ unsigned int i, nr_pages = 0;
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
@@ -4302,7 +4302,19 @@ unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
kvm_for_each_memslot(memslot, slots)
nr_pages += memslot->npages;
- nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
+ if (tdp_enabled) {
+ /* one root page */
+ nr_mmu_pages = 1;
+ /* nr_pages / (512^i) per level, due to
+ * guest RAM map being linear */
+ for (i = 1; i < 4; i++) {
+ int nr_pages_round = nr_pages + (1 << (9*i));
+ nr_mmu_pages += nr_pages_round >> (9*i);
+ }
+ } else {
+ nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
+ }
+
nr_mmu_pages = max(nr_mmu_pages,
(unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
--
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