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Date: Fri, 7 Apr 2023 20:19:21 +0000
From: Sagi Shahar <sagis@...gle.com>
To: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, x86@...nel.org
Cc: Sean Christopherson <seanjc@...gle.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Isaku Yamahata <isaku.yamahata@...el.com>,
Erdem Aktas <erdemaktas@...gle.com>,
David Matlack <dmatlack@...gle.com>,
Kai Huang <kai.huang@...el.com>,
Zhi Wang <zhi.wang.linux@...il.com>,
Chao Peng <chao.p.peng@...ux.intel.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Sagi Shahar <sagis@...gle.com>
Subject: [RFC PATCH 5/5] KVM: TDX: Add core logic for TDX intra-host migration
Adds the core logic for transferring state between source and
destination TDs during intra-host migration.
Signed-off-by: Sagi Shahar <sagis@...gle.com>
---
arch/x86/kvm/vmx/tdx.c | 191 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 190 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 0999a6d827c99..05b164a91437b 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -2834,9 +2834,198 @@ static __always_inline bool tdx_guest(struct kvm *kvm)
return tdx_kvm->finalized;
}
+#define for_each_memslot_pair(memslots_1, memslots_2, memslot_iter_1, \
+ memslot_iter_2) \
+ for (memslot_iter_1 = rb_first(&memslots_1->gfn_tree), \
+ memslot_iter_2 = rb_first(&memslots_2->gfn_tree); \
+ memslot_iter_1 && memslot_iter_2; \
+ memslot_iter_1 = rb_next(memslot_iter_1), \
+ memslot_iter_2 = rb_next(memslot_iter_2))
+
static int tdx_migrate_from(struct kvm *dst, struct kvm *src)
{
- return -EINVAL;
+ struct rb_node *src_memslot_iter, *dst_memslot_iter;
+ struct vcpu_tdx *dst_tdx_vcpu, *src_tdx_vcpu;
+ struct kvm_memslots *src_slots, *dst_slots;
+ struct kvm_vcpu *dst_vcpu, *src_vcpu;
+ struct kvm_tdx *src_tdx, *dst_tdx;
+ unsigned long i, j;
+ int ret;
+
+ src_tdx = to_kvm_tdx(src);
+ dst_tdx = to_kvm_tdx(dst);
+
+ src_slots = __kvm_memslots(src, 0);
+ dst_slots = __kvm_memslots(dst, 0);
+
+ ret = -EINVAL;
+
+ if (!src_tdx->finalized) {
+ pr_warn("Cannot migrate from a non finalized VM\n");
+ goto abort;
+ }
+
+ // Traverse both memslots in gfn order and compare them
+ for_each_memslot_pair(src_slots, dst_slots, src_memslot_iter, dst_memslot_iter) {
+ struct kvm_memory_slot *src_slot, *dst_slot;
+
+ src_slot =
+ container_of(src_memslot_iter, struct kvm_memory_slot,
+ gfn_node[src_slots->node_idx]);
+ dst_slot =
+ container_of(src_memslot_iter, struct kvm_memory_slot,
+ gfn_node[dst_slots->node_idx]);
+
+ if (src_slot->base_gfn != dst_slot->base_gfn ||
+ src_slot->npages != dst_slot->npages) {
+ pr_warn("Cannot migrate between VMs with different memory slots configurations\n");
+ goto abort;
+ }
+
+ if (src_slot->flags != dst_slot->flags) {
+ pr_warn("Cannot migrate between VMs with different memory slots configurations\n");
+ goto abort;
+ }
+
+ if (src_slot->flags & KVM_MEM_PRIVATE) {
+ if (src_slot->restrictedmem.file->f_inode->i_ino !=
+ dst_slot->restrictedmem.file->f_inode->i_ino) {
+ pr_warn("Private memslots points to different restricted files\n");
+ goto abort;
+ }
+
+ if (src_slot->restrictedmem.index != dst_slot->restrictedmem.index) {
+ pr_warn("Private memslots points to the restricted file at different offsets\n");
+ goto abort;
+ }
+ }
+ }
+
+ if (src_memslot_iter || dst_memslot_iter) {
+ pr_warn("Cannot migrate between VMs with different memory slots configurations\n");
+ goto abort;
+ }
+
+ dst_tdx->hkid = src_tdx->hkid;
+ dst_tdx->tdr_pa = src_tdx->tdr_pa;
+
+ dst_tdx->tdcs_pa = kcalloc(tdx_info.nr_tdcs_pages, sizeof(*dst_tdx->tdcs_pa),
+ GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+ if (!dst_tdx->tdcs_pa) {
+ ret = -ENOMEM;
+ goto late_abort;
+ }
+ memcpy(dst_tdx->tdcs_pa, src_tdx->tdcs_pa,
+ tdx_info.nr_tdcs_pages * sizeof(*dst_tdx->tdcs_pa));
+
+ dst_tdx->tsc_offset = src_tdx->tsc_offset;
+ dst_tdx->attributes = src_tdx->attributes;
+ dst_tdx->xfam = src_tdx->xfam;
+ dst_tdx->kvm.arch.gfn_shared_mask = src_tdx->kvm.arch.gfn_shared_mask;
+
+ kvm_for_each_vcpu(i, src_vcpu, src)
+ tdx_flush_vp_on_cpu(src_vcpu);
+
+ /* Copy per-vCPU state */
+ kvm_for_each_vcpu(i, src_vcpu, src) {
+ src_tdx_vcpu = to_tdx(src_vcpu);
+ dst_vcpu = kvm_get_vcpu(dst, i);
+ dst_tdx_vcpu = to_tdx(dst_vcpu);
+
+ vcpu_load(dst_vcpu);
+
+ memcpy(dst_vcpu->arch.regs, src_vcpu->arch.regs,
+ NR_VCPU_REGS * sizeof(src_vcpu->arch.regs[0]));
+ dst_vcpu->arch.regs_avail = src_vcpu->arch.regs_avail;
+ dst_vcpu->arch.regs_dirty = src_vcpu->arch.regs_dirty;
+
+ dst_vcpu->arch.tsc_offset = dst_tdx->tsc_offset;
+
+ dst_tdx_vcpu->interrupt_disabled_hlt = src_tdx_vcpu->interrupt_disabled_hlt;
+ dst_tdx_vcpu->buggy_hlt_workaround = src_tdx_vcpu->buggy_hlt_workaround;
+
+ dst_tdx_vcpu->tdvpr_pa = src_tdx_vcpu->tdvpr_pa;
+ dst_tdx_vcpu->tdvpx_pa = kcalloc(tdx_info.nr_tdvpx_pages,
+ sizeof(*dst_tdx_vcpu->tdvpx_pa),
+ GFP_KERNEL_ACCOUNT);
+ if (!dst_tdx_vcpu->tdvpx_pa) {
+ ret = -ENOMEM;
+ vcpu_put(dst_vcpu);
+ goto late_abort;
+ }
+ memcpy(dst_tdx_vcpu->tdvpx_pa, src_tdx_vcpu->tdvpx_pa,
+ tdx_info.nr_tdvpx_pages * sizeof(*dst_tdx_vcpu->tdvpx_pa));
+
+ td_vmcs_write64(dst_tdx_vcpu, POSTED_INTR_DESC_ADDR, __pa(&dst_tdx_vcpu->pi_desc));
+
+ /* Copy private EPT tables */
+ if (kvm_mmu_move_private_pages_from(dst_vcpu, src_vcpu)) {
+ ret = -EINVAL;
+ vcpu_put(dst_vcpu);
+ goto late_abort;
+ }
+
+ for (j = 0; j < tdx_info.nr_tdvpx_pages; j++)
+ src_tdx_vcpu->tdvpx_pa[j] = 0;
+
+ src_tdx_vcpu->tdvpr_pa = 0;
+
+ vcpu_put(dst_vcpu);
+ }
+
+ for_each_memslot_pair(src_slots, dst_slots, src_memslot_iter,
+ dst_memslot_iter) {
+ struct kvm_memory_slot *src_slot, *dst_slot;
+
+ src_slot = container_of(src_memslot_iter,
+ struct kvm_memory_slot,
+ gfn_node[src_slots->node_idx]);
+ dst_slot = container_of(src_memslot_iter,
+ struct kvm_memory_slot,
+ gfn_node[dst_slots->node_idx]);
+
+ for (i = 1; i < KVM_NR_PAGE_SIZES; ++i) {
+ unsigned long ugfn;
+ int level = i + 1;
+
+ /*
+ * If the gfn and userspace address are not aligned wrt each other, then
+ * large page support should already be disabled at this level.
+ */
+ ugfn = dst_slot->userspace_addr >> PAGE_SHIFT;
+ if ((dst_slot->base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE(level) - 1))
+ continue;
+
+ dst_slot->arch.lpage_info[i - 1] =
+ src_slot->arch.lpage_info[i - 1];
+ src_slot->arch.lpage_info[i - 1] = NULL;
+ }
+ }
+
+ dst->mem_attr_array.xa_head = src->mem_attr_array.xa_head;
+ src->mem_attr_array.xa_head = NULL;
+
+ dst_tdx->finalized = true;
+
+ /* Clear source VM to avoid freeing the hkid and pages on VM put */
+ src_tdx->hkid = -1;
+ src_tdx->tdr_pa = 0;
+ for (i = 0; i < tdx_info.nr_tdcs_pages; i++)
+ src_tdx->tdcs_pa[i] = 0;
+
+ return 0;
+
+late_abort:
+ /* If we aborted after the state transfer already started, the src VM
+ * is no longer valid.
+ */
+ kvm_vm_dead(src);
+
+abort:
+ dst_tdx->hkid = -1;
+ dst_tdx->tdr_pa = 0;
+
+ return ret;
}
int tdx_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd)
--
2.40.0.348.gf938b09366-goog
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