This will handle RMP table updates and direct map changes needed for page state conversions requested by userspace. Signed-off-by: Michael Roth <michael.roth@xxxxxxx> --- arch/x86/kvm/svm/sev.c | 126 +++++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/svm/svm.c | 1 + arch/x86/kvm/svm/svm.h | 2 + 3 files changed, 129 insertions(+) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index b2f1a12685ed..73d614c538da 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -3381,6 +3381,31 @@ static int snp_rmptable_psmash(struct kvm *kvm, kvm_pfn_t pfn) return psmash(pfn); } +static int snp_make_page_shared(struct kvm *kvm, gpa_t gpa, kvm_pfn_t pfn, int level) +{ + int rc, rmp_level; + + rc = snp_lookup_rmpentry(pfn, &rmp_level); + if (rc < 0) + return -EINVAL; + + /* If page is not assigned then do nothing */ + if (!rc) + return 0; + + /* + * Is the page part of an existing 2MB RMP entry ? Split the 2MB into + * multiple of 4K-page before making the memory shared. + */ + if (level == PG_LEVEL_4K && rmp_level == PG_LEVEL_2M) { + rc = snp_rmptable_psmash(kvm, pfn); + if (rc) + return rc; + } + + return rmp_make_shared(pfn, level); +} + /* * TODO: need to get the value set by userspace in vcpu->run->vmgexit.ghcb_msr * and process that here accordingly. @@ -4373,3 +4398,104 @@ void handle_rmp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code) kvm_zap_gfn_range(kvm, gfn, gfn + PTRS_PER_PMD); put_page(pfn_to_page(pfn)); } + +static inline u8 order_to_level(int order) +{ + BUILD_BUG_ON(KVM_MAX_HUGEPAGE_LEVEL > PG_LEVEL_1G); + + if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_1G)) + return PG_LEVEL_1G; + + if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M)) + return PG_LEVEL_2M; + + return PG_LEVEL_4K; +} + +int sev_update_mem_attr(struct kvm_memory_slot *slot, unsigned int attr, + gfn_t start, gfn_t end) +{ + struct kvm_sev_info *sev = &to_kvm_svm(slot->kvm)->sev_info; + enum psc_op op = (attr & KVM_MEMORY_ATTRIBUTE_PRIVATE) ? SNP_PAGE_STATE_PRIVATE + : SNP_PAGE_STATE_SHARED; + gfn_t gfn = start; + + pr_debug("%s: GFN 0x%llx - 0x%llx, op: %d\n", __func__, start, end, op); + + if (!sev_snp_guest(slot->kvm)) + return 0; + + if (!kvm_slot_can_be_private(slot)) { + pr_err_ratelimited("%s: memslot for gfn: 0x%llx is not private.\n", + __func__, gfn); + return -EPERM; + } + + while (gfn < end) { + kvm_pfn_t pfn; + int level = PG_LEVEL_4K; /* TODO: take actual order into account */ + gpa_t gpa = gfn_to_gpa(gfn); + int npages = 1; + int order; + int rc; + + /* + * No work to do if there was never a page allocated from private + * memory. If there was a page that was deallocated previously, + * the invalidation notifier should have restored the page to + * shared. + */ + rc = kvm_restrictedmem_get_pfn(slot, gfn, &pfn, &order); + if (rc) { + pr_warn_ratelimited("%s: failed to retrieve gfn 0x%llx from private FD\n", + __func__, gfn); + gfn++; + continue; + } + + /* + * TODO: The RMP entry's hugepage bit is ignored for + * shared/unassigned pages. Either handle looping through each + * sub-page as part of snp_make_page_shared(), or remove the + * level argument. + */ + if (op == SNP_PAGE_STATE_PRIVATE && order && + IS_ALIGNED(gfn, 1 << order) && (gfn + (1 << order)) <= end) { + level = order_to_level(order); + npages = 1 << order; + } + + /* + * Grab the PFN from private memslot and update the RMP entry. + * It may be worthwhile to go ahead and map it into the TDP at + * this point if the guest is doing lazy acceptance, but for + * up-front bulk shared->private conversions it's not likely + * the guest will try to access the PFN any time soon, so for + * now just take the let KVM MMU handle faulting it on the next + * access. + */ + switch (op) { + case SNP_PAGE_STATE_SHARED: + rc = snp_make_page_shared(slot->kvm, gpa, pfn, level); + break; + case SNP_PAGE_STATE_PRIVATE: + rc = rmp_make_private(pfn, gpa, level, sev->asid, false); + break; + default: + rc = PSC_INVALID_ENTRY; + break; + } + + put_page(pfn_to_page(pfn)); + + if (rc) { + pr_err_ratelimited("%s: failed op %d gpa %llx pfn %llx level %d rc %d\n", + __func__, op, gpa, pfn, level, rc); + return -EINVAL; + } + + gfn += npages; + } + + return 0; +} diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 539926b07ee5..e2edc4700e55 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4860,6 +4860,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { .alloc_apic_backing_page = svm_alloc_apic_backing_page, .adjust_mapping_level = sev_adjust_mapping_level, + .update_mem_attr = sev_update_mem_attr, }; /* diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 37bd7b728d52..50a2bcaf3fd7 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -725,6 +725,8 @@ struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu); void sev_adjust_mapping_level(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int *level); void handle_rmp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code); void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu); +int sev_update_mem_attr(struct kvm_memory_slot *slot, unsigned int attr, + gfn_t start, gfn_t end); /* vmenter.S */ -- 2.25.1