Merge: x86/hyperv: Fix kdump on Azure CVMs
MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/7349 JIRA: https://issues.redhat.com/browse/RHEL-70228 Fix kdump on Azure CVMs. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Approved-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Approved-by: Maxim Levitsky <mlevitsk@redhat.com> Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com> Merged-by: Patrick Talbert <ptalbert@redhat.com>
This commit is contained in:
Patrick Talbert
commit
e32f525179
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@ -462,6 +462,195 @@ void hv_ivm_msr_read(u64 msr, u64 *value)
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hv_ghcb_msr_read(msr, value);
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}
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/*
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* Keep track of the PFN regions which were shared with the host. The access
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* must be revoked upon kexec/kdump (see hv_ivm_clear_host_access()).
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*/
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struct hv_enc_pfn_region {
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struct list_head list;
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u64 pfn;
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int count;
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};
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static LIST_HEAD(hv_list_enc);
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static DEFINE_RAW_SPINLOCK(hv_list_enc_lock);
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static int hv_list_enc_add(const u64 *pfn_list, int count)
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{
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struct hv_enc_pfn_region *ent;
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unsigned long flags;
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u64 pfn;
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int i;
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for (i = 0; i < count; i++) {
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pfn = pfn_list[i];
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raw_spin_lock_irqsave(&hv_list_enc_lock, flags);
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/* Check if the PFN already exists in some region first */
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list_for_each_entry(ent, &hv_list_enc, list) {
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if ((ent->pfn <= pfn) && (ent->pfn + ent->count - 1 >= pfn))
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/* Nothing to do - pfn is already in the list */
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goto unlock_done;
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}
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/*
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* Check if the PFN is adjacent to an existing region. Growing
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* a region can make it adjacent to another one but merging is
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* not (yet) implemented for simplicity. A PFN cannot be added
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* to two regions to keep the logic in hv_list_enc_remove()
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* correct.
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*/
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list_for_each_entry(ent, &hv_list_enc, list) {
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if (ent->pfn + ent->count == pfn) {
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/* Grow existing region up */
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ent->count++;
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goto unlock_done;
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} else if (pfn + 1 == ent->pfn) {
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/* Grow existing region down */
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ent->pfn--;
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ent->count++;
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goto unlock_done;
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}
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}
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raw_spin_unlock_irqrestore(&hv_list_enc_lock, flags);
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/* No adjacent region found -- create a new one */
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ent = kzalloc(sizeof(struct hv_enc_pfn_region), GFP_KERNEL);
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if (!ent)
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return -ENOMEM;
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ent->pfn = pfn;
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ent->count = 1;
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raw_spin_lock_irqsave(&hv_list_enc_lock, flags);
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list_add(&ent->list, &hv_list_enc);
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unlock_done:
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raw_spin_unlock_irqrestore(&hv_list_enc_lock, flags);
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}
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return 0;
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}
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static int hv_list_enc_remove(const u64 *pfn_list, int count)
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{
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struct hv_enc_pfn_region *ent, *t;
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struct hv_enc_pfn_region new_region;
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unsigned long flags;
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u64 pfn;
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int i;
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for (i = 0; i < count; i++) {
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pfn = pfn_list[i];
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raw_spin_lock_irqsave(&hv_list_enc_lock, flags);
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list_for_each_entry_safe(ent, t, &hv_list_enc, list) {
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if (pfn == ent->pfn + ent->count - 1) {
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/* Removing tail pfn */
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ent->count--;
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if (!ent->count) {
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list_del(&ent->list);
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kfree(ent);
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}
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goto unlock_done;
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} else if (pfn == ent->pfn) {
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/* Removing head pfn */
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ent->count--;
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ent->pfn++;
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if (!ent->count) {
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list_del(&ent->list);
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kfree(ent);
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}
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goto unlock_done;
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} else if (pfn > ent->pfn && pfn < ent->pfn + ent->count - 1) {
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/*
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* Removing a pfn in the middle. Cut off the tail
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* of the existing region and create a template for
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* the new one.
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*/
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new_region.pfn = pfn + 1;
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new_region.count = ent->count - (pfn - ent->pfn + 1);
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ent->count = pfn - ent->pfn;
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goto unlock_split;
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}
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}
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unlock_done:
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raw_spin_unlock_irqrestore(&hv_list_enc_lock, flags);
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continue;
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unlock_split:
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raw_spin_unlock_irqrestore(&hv_list_enc_lock, flags);
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ent = kzalloc(sizeof(struct hv_enc_pfn_region), GFP_KERNEL);
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if (!ent)
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return -ENOMEM;
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ent->pfn = new_region.pfn;
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ent->count = new_region.count;
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raw_spin_lock_irqsave(&hv_list_enc_lock, flags);
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list_add(&ent->list, &hv_list_enc);
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raw_spin_unlock_irqrestore(&hv_list_enc_lock, flags);
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}
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return 0;
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}
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/* Stop new private<->shared conversions */
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static void hv_vtom_kexec_begin(void)
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{
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if (!IS_ENABLED(CONFIG_KEXEC_CORE))
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return;
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/*
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* Crash kernel reaches here with interrupts disabled: can't wait for
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* conversions to finish.
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*
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* If race happened, just report and proceed.
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*/
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if (!set_memory_enc_stop_conversion())
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pr_warn("Failed to stop shared<->private conversions\n");
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}
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static void hv_vtom_kexec_finish(void)
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{
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struct hv_gpa_range_for_visibility *input;
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struct hv_enc_pfn_region *ent;
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unsigned long flags;
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u64 hv_status;
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int cur, i;
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local_irq_save(flags);
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input = *this_cpu_ptr(hyperv_pcpu_input_arg);
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if (unlikely(!input))
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goto out;
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list_for_each_entry(ent, &hv_list_enc, list) {
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for (i = 0, cur = 0; i < ent->count; i++) {
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input->gpa_page_list[cur] = ent->pfn + i;
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cur++;
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if (cur == HV_MAX_MODIFY_GPA_REP_COUNT || i == ent->count - 1) {
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input->partition_id = HV_PARTITION_ID_SELF;
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input->host_visibility = VMBUS_PAGE_NOT_VISIBLE;
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input->reserved0 = 0;
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input->reserved1 = 0;
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hv_status = hv_do_rep_hypercall(
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HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY,
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cur, 0, input, NULL);
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WARN_ON_ONCE(!hv_result_success(hv_status));
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cur = 0;
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}
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}
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}
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out:
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local_irq_restore(flags);
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}
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/*
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* hv_mark_gpa_visibility - Set pages visible to host via hvcall.
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*
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@ -475,6 +664,7 @@ static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
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struct hv_gpa_range_for_visibility *input;
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u64 hv_status;
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unsigned long flags;
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int ret;
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/* no-op if partition isolation is not enabled */
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if (!hv_is_isolation_supported())
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@ -486,6 +676,13 @@ static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
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return -EINVAL;
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}
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if (visibility == VMBUS_PAGE_NOT_VISIBLE)
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ret = hv_list_enc_remove(pfn, count);
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else
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ret = hv_list_enc_add(pfn, count);
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if (ret)
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return ret;
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local_irq_save(flags);
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input = *this_cpu_ptr(hyperv_pcpu_input_arg);
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@ -506,8 +703,18 @@ static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
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if (hv_result_success(hv_status))
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return 0;
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if (visibility == VMBUS_PAGE_NOT_VISIBLE)
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ret = hv_list_enc_add(pfn, count);
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else
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return -EFAULT;
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ret = hv_list_enc_remove(pfn, count);
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/*
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* There's no good way to recover from -ENOMEM here, the accounting is
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* wrong either way.
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*/
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WARN_ON_ONCE(ret);
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return -EFAULT;
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}
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/*
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@ -669,6 +876,8 @@ void __init hv_vtom_init(void)
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x86_platform.guest.enc_tlb_flush_required = hv_vtom_tlb_flush_required;
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x86_platform.guest.enc_status_change_prepare = hv_vtom_clear_present;
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x86_platform.guest.enc_status_change_finish = hv_vtom_set_host_visibility;
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x86_platform.guest.enc_kexec_begin = hv_vtom_kexec_begin;
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x86_platform.guest.enc_kexec_finish = hv_vtom_kexec_finish;
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/* Set WB as the default cache mode. */
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mtrr_overwrite_state(NULL, 0, MTRR_TYPE_WRBACK);
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