Merge tag 'kvm-x86-docs-6.7' of https://github.com/kvm-x86/linux into HEAD

KVM x86 Documentation updates for 6.7:

 - Fix various typos, notably a confusing reference to the non-existent
   "struct kvm_vcpu_event" (the actual structure is kvm_vcpu_events, plural).

 - Update x86's kvm_mmu_page documentation to bring it closer to the code
   (this raced with the removal of async zapping and so the documentation is
   already stale; my bad).

 - Document the behavior of x86 PMU filters on fixed counters.

Author: bonzini

Documentation/virt/kvm/api.rst

@@ -547,7 +547,7 @@ ioctl is useful if the in-kernel PIC is not used.
 PPC:
 ^^^^
 
-Queues an external interrupt to be injected. This ioctl is overleaded
+Queues an external interrupt to be injected. This ioctl is overloaded
 with 3 different irq values:
 
 a) KVM_INTERRUPT_SET
@@ -998,7 +998,7 @@ be set in the flags field of this ioctl:
 The KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL flag requests KVM to generate
 the contents of the hypercall page automatically; hypercalls will be
 intercepted and passed to userspace through KVM_EXIT_XEN.  In this
-ase, all of the blob size and address fields must be zero.
+case, all of the blob size and address fields must be zero.
 
 The KVM_XEN_HVM_CONFIG_EVTCHN_SEND flag indicates to KVM that userspace
 will always use the KVM_XEN_HVM_EVTCHN_SEND ioctl to deliver event
@@ -1103,7 +1103,7 @@ Other flags returned by ``KVM_GET_CLOCK`` are accepted but ignored.
 :Extended by: KVM_CAP_INTR_SHADOW
 :Architectures: x86, arm64
 :Type: vcpu ioctl
-:Parameters: struct kvm_vcpu_event (out)
+:Parameters: struct kvm_vcpu_events (out)
 :Returns: 0 on success, -1 on error
 
 X86:
@@ -1226,7 +1226,7 @@ directly to the virtual CPU).
 :Extended by: KVM_CAP_INTR_SHADOW
 :Architectures: x86, arm64
 :Type: vcpu ioctl
-:Parameters: struct kvm_vcpu_event (in)
+:Parameters: struct kvm_vcpu_events (in)
 :Returns: 0 on success, -1 on error
 
 X86:
@@ -3115,7 +3115,7 @@ as follow::
    };
 
 An entry with a "page_shift" of 0 is unused. Because the array is
-organized in increasing order, a lookup can stop when encoutering
+organized in increasing order, a lookup can stop when encountering
 such an entry.
 
 The "slb_enc" field provides the encoding to use in the SLB for the
@@ -3507,7 +3507,7 @@ Possible features:
 	      - KVM_RUN and KVM_GET_REG_LIST are not available;
 
 	      - KVM_GET_ONE_REG and KVM_SET_ONE_REG cannot be used to access
-	        the scalable archietctural SVE registers
+	        the scalable architectural SVE registers
 	        KVM_REG_ARM64_SVE_ZREG(), KVM_REG_ARM64_SVE_PREG() or
 	        KVM_REG_ARM64_SVE_FFR;
 
@@ -4453,7 +4453,7 @@ This will have undefined effects on the guest if it has not already
 placed itself in a quiescent state where no vcpu will make MMU enabled
 memory accesses.
 
-On succsful completion, the pending HPT will become the guest's active
+On successful completion, the pending HPT will become the guest's active
 HPT and the previous HPT will be discarded.
 
 On failure, the guest will still be operating on its previous HPT.
@@ -5068,7 +5068,7 @@ before the vcpu is fully usable.
 
 Between KVM_ARM_VCPU_INIT and KVM_ARM_VCPU_FINALIZE, the feature may be
 configured by use of ioctls such as KVM_SET_ONE_REG.  The exact configuration
-that should be performaned and how to do it are feature-dependent.
+that should be performed and how to do it are feature-dependent.
 
 Other calls that depend on a particular feature being finalized, such as
 KVM_RUN, KVM_GET_REG_LIST, KVM_GET_ONE_REG and KVM_SET_ONE_REG, will fail with
@@ -5176,6 +5176,24 @@ Valid values for 'action'::
   #define KVM_PMU_EVENT_ALLOW 0
   #define KVM_PMU_EVENT_DENY 1
 
+Via this API, KVM userspace can also control the behavior of the VM's fixed
+counters (if any) by configuring the "action" and "fixed_counter_bitmap" fields.
+
+Specifically, KVM follows the following pseudo-code when determining whether to
+allow the guest FixCtr[i] to count its pre-defined fixed event::
+
+  FixCtr[i]_is_allowed = (action == ALLOW) && (bitmap & BIT(i)) ||
+    (action == DENY) && !(bitmap & BIT(i));
+  FixCtr[i]_is_denied = !FixCtr[i]_is_allowed;
+
+KVM always consumes fixed_counter_bitmap, it's userspace's responsibility to
+ensure fixed_counter_bitmap is set correctly, e.g. if userspace wants to define
+a filter that only affects general purpose counters.
+
+Note, the "events" field also applies to fixed counters' hardcoded event_select
+and unit_mask values.  "fixed_counter_bitmap" has higher priority than "events"
+if there is a contradiction between the two.
+
 4.121 KVM_PPC_SVM_OFF
 ---------------------
 
@@ -5527,7 +5545,7 @@ KVM_XEN_ATTR_TYPE_EVTCHN
   from the guest. A given sending port number may be directed back to
   a specified vCPU (by APIC ID) / port / priority on the guest, or to
   trigger events on an eventfd. The vCPU and priority can be changed
-  by setting KVM_XEN_EVTCHN_UPDATE in a subsequent call, but but other
+  by setting KVM_XEN_EVTCHN_UPDATE in a subsequent call, but other
   fields cannot change for a given sending port. A port mapping is
   removed by using KVM_XEN_EVTCHN_DEASSIGN in the flags field. Passing
   KVM_XEN_EVTCHN_RESET in the flags field removes all interception of

Documentation/virt/kvm/x86/mmu.rst

@@ -202,10 +202,22 @@ Shadow pages contain the following information:
     Is 1 if the MMU instance cannot use A/D bits.  EPT did not have A/D
     bits before Haswell; shadow EPT page tables also cannot use A/D bits
     if the L1 hypervisor does not enable them.
+  role.guest_mode:
+    Indicates the shadow page is created for a nested guest.
   role.passthrough:
     The page is not backed by a guest page table, but its first entry
     points to one.  This is set if NPT uses 5-level page tables (host
     CR4.LA57=1) and is shadowing L1's 4-level NPT (L1 CR4.LA57=0).
+  mmu_valid_gen:
+    The MMU generation of this page, used to fast zap of all MMU pages within a
+    VM without blocking vCPUs too long. Specifically, KVM updates the per-VM
+    valid MMU generation which causes the mismatch of mmu_valid_gen for each mmu
+    page. This makes all existing MMU pages obsolete. Obsolete pages can't be
+    used. Therefore, vCPUs must load a new, valid root before re-entering the
+    guest. The MMU generation is only ever '0' or '1'. Note, the TDP MMU doesn't
+    use this field as non-root TDP MMU pages are reachable only from their
+    owning root. Thus it suffices for TDP MMU to use role.invalid in root pages
+    to invalidate all MMU pages.
   gfn:
     Either the guest page table containing the translations shadowed by this
     page, or the base page frame for linear translations.  See role.direct.
@@ -219,21 +231,30 @@ Shadow pages contain the following information:
     at __pa(sp2->spt).  sp2 will point back at sp1 through parent_pte.
     The spt array forms a DAG structure with the shadow page as a node, and
     guest pages as leaves.
-  gfns:
-    An array of 512 guest frame numbers, one for each present pte.  Used to
-    perform a reverse map from a pte to a gfn. When role.direct is set, any
-    element of this array can be calculated from the gfn field when used, in
-    this case, the array of gfns is not allocated. See role.direct and gfn.
-  root_count:
-    A counter keeping track of how many hardware registers (guest cr3 or
-    pdptrs) are now pointing at the page.  While this counter is nonzero, the
-    page cannot be destroyed.  See role.invalid.
+  shadowed_translation:
+    An array of 512 shadow translation entries, one for each present pte. Used
+    to perform a reverse map from a pte to a gfn as well as its access
+    permission. When role.direct is set, the shadow_translation array is not
+    allocated. This is because the gfn contained in any element of this array
+    can be calculated from the gfn field when used.  In addition, when
+    role.direct is set, KVM does not track access permission for each of the
+    gfn. See role.direct and gfn.
+  root_count / tdp_mmu_root_count:
+     root_count is a reference counter for root shadow pages in Shadow MMU.
+     vCPUs elevate the refcount when getting a shadow page that will be used as
+     a root page, i.e. page that will be loaded into hardware directly (CR3,
+     PDPTRs, nCR3 EPTP). Root pages cannot be destroyed while their refcount is
+     non-zero. See role.invalid. tdp_mmu_root_count is similar but exclusively
+     used in TDP MMU as an atomic refcount.
   parent_ptes:
     The reverse mapping for the pte/ptes pointing at this page's spt. If
     parent_ptes bit 0 is zero, only one spte points at this page and
     parent_ptes points at this single spte, otherwise, there exists multiple
     sptes pointing at this page and (parent_ptes & ~0x1) points at a data
     structure with a list of parent sptes.
+  ptep:
+    The kernel virtual address of the SPTE that points at this shadow page.
+    Used exclusively by the TDP MMU, this field is a union with parent_ptes.
   unsync:
     If true, then the translations in this page may not match the guest's
     translation.  This is equivalent to the state of the tlb when a pte is
@@ -261,6 +282,10 @@ Shadow pages contain the following information:
     since the last time the page table was actually used; if emulation
     is triggered too frequently on this page, KVM will unmap the page
     to avoid emulation in the future.
+  tdp_mmu_page:
+    Is 1 if the shadow page is a TDP MMU page. This variable is used to
+    bifurcate the control flows for KVM when walking any data structure that
+    may contain pages from both TDP MMU and shadow MMU.
 
 Reverse map
 ===========