On 17/03/21 11:53, Marc Zyngier wrote:
On Wed, 17 Mar 2021 10:40:23 +0000,
Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
On 17/03/21 10:10, Marc Zyngier wrote:
@@ -366,7 +366,7 @@ static int hyp_map_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
if (WARN_ON(level == KVM_PGTABLE_MAX_LEVELS - 1))
return -EINVAL;
- childp = (kvm_pte_t *)get_zeroed_page(GFP_KERNEL);
+ childp = (kvm_pte_t *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
No, this is wrong.
You cannot account the hypervisor page tables to the guest because we
don't ever unmap them, and that we can't distinguish two data
structures from two different VMs occupying the same page.
If you never unmap them, there should at least be a shrinker to get
rid of unused pages in the event of memory pressure.
We don't track where these pages are coming from or whether they can
safely be unmapped. Until we can track such ownership and deal with
page sharing, these mappings have to stay,
At most, this represent the amount of memory required to map the whole
of the linear mapping.
Ah, these are the EL2 pages, not the stage2 page tables, right? If so,
sorry for the noise.
Paolo
