From 066be0958686f2c849bc78a712b5c3dc6d7e6e8e Mon Sep 17 00:00:00 2001 From: Alexandru Elisei Date: Tue, 1 Sep 2020 14:33:56 +0100 Subject: [PATCH] KVM: arm64: Update page shift if stage 2 block mapping not supported Commit 4405434f6ef18 (" KVM: arm/arm64: Signal SIGBUS when stage2 discovers hwpoison memory") modifies user_mem_abort() to send a SIGBUS signal when the fault IPA maps to a hwpoisoned page. Commit 3d8e6655d49e ("KVM: arm/arm64: Re-check VMA on detecting a poisoned page") changed kvm_send_hwpoison_signal() to use the page shift instead of the VMA because at that point the code had already released the mmap lock, which means userspace could have modified the VMA. If userspace uses hugetlbfs for the VM memory, user_mem_abort() tries to map the guest fault IPA using block mappings in stage 2. That is not always possible, if, for example, userspace uses dirty page logging for the VM. Update the page shift appropriately in those cases when we downgrade the stage 2 entry from a block mapping to a page. Fixes: 3d8e6655d49e ("KVM: arm/arm64: Re-check VMA on detecting a poisoned page") Signed-off-by: Alexandru Elisei Signed-off-by: Marc Zyngier Reviewed-by: Gavin Shan Link: https://lore.kernel.org/r/20200901133357.52640-2-alexandru.elisei@arm.com --- arch/arm64/kvm/mmu.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 16b8660ddbccd..f58d657a898df 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1871,6 +1871,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, !fault_supports_stage2_huge_mapping(memslot, hva, vma_pagesize)) { force_pte = true; vma_pagesize = PAGE_SIZE; + vma_shift = PAGE_SHIFT; } /* -- 2.39.5