[RFC PATCH v6 41/92] KVM: MMU: Enable Lazy mode SPPT setup
From: Adalbert Lazăr <hidden>
Date: 2019-08-09 16:02:58
Also in:
kvm, linux-mm
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Yang Weijiang <redacted> If SPP subpages are set while the physical page are not available in EPT leaf entry, the mapping is first stored in SPP access bitmap buffer. SPPT setup is deferred to access to the protected page, in EPT page fault handler, the SPPT enries are set up. Signed-off-by: Yang Weijiang <redacted> Message-Id: [off-list ref] Signed-off-by: Adalbert Lazăr <redacted> --- arch/x86/kvm/mmu.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d59108a3ebbf..24222e3add91 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c@@ -4400,6 +4400,26 @@ check_hugepage_cache_consistency(struct kvm_vcpu *vcpu, gfn_t gfn, int level) return kvm_mtrr_check_gfn_range_consistency(vcpu, gfn, page_num); } +static int kvm_enable_spp_protection(struct kvm *kvm, u64 gfn) +{ + struct kvm_subpage spp_info = {0}; + struct kvm_memory_slot *slot; + + slot = gfn_to_memslot(kvm, gfn); + if (!slot) + return -EFAULT; + + spp_info.base_gfn = gfn; + spp_info.npages = 1; + + if (kvm_mmu_get_subpages(kvm, &spp_info, true) < 0) + return -EFAULT; + + if (spp_info.access_map[0] != FULL_SPP_ACCESS) + kvm_mmu_set_subpages(kvm, &spp_info, true); + + return 0; +} static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code, bool prefault) {
@@ -4451,6 +4471,10 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code, if (likely(!force_pt_level)) transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level); r = __direct_map(vcpu, write, map_writable, level, gfn, pfn, prefault); + + if (vcpu->kvm->arch.spp_active && level == PT_PAGE_TABLE_LEVEL) + kvm_enable_spp_protection(vcpu->kvm, gfn); + spin_unlock(&vcpu->kvm->mmu_lock); return r;
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