Rust-for-Linux
diff --git a/‎Documentation/virt/kvm/api.rst‎
Lines changed: 235 additions & 9 deletions b/‎Documentation/virt/kvm/api.rst‎
Lines changed: 235 additions & 9 deletions
@@ -147,10 +147,29 @@ described as 'basic' will be available.
 The new VM has no virtual cpus and no memory.
 You probably want to use 0 as machine type.
 
+X86:
+^^^^
+
+Supported X86 VM types can be queried via KVM_CAP_VM_TYPES.
+
+S390:
+^^^^^
+
 In order to create user controlled virtual machines on S390, check
 KVM_CAP_S390_UCONTROL and use the flag KVM_VM_S390_UCONTROL as
 privileged user (CAP_SYS_ADMIN).
 
+MIPS:
+^^^^^
+
+To use hardware assisted virtualization on MIPS (VZ ASE) rather than
+the default trap & emulate implementation (which changes the virtual
+memory layout to fit in user mode), check KVM_CAP_MIPS_VZ and use the
+flag KVM_VM_MIPS_VZ.
+
+ARM64:
+^^^^^^
+
 On arm64, the physical address size for a VM (IPA Size limit) is limited
 to 40bits by default. The limit can be configured if the host supports the
 extension KVM_CAP_ARM_VM_IPA_SIZE. When supported, use
@@ -540,7 +559,7 @@ 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
@@ -965,7 +984,7 @@ 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
@@ -1070,7 +1089,7 @@ 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:
@@ -1193,7 +1212,7 @@ 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:
@@ -3063,7 +3082,7 @@ 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
@@ -3455,7 +3474,7 @@ 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;
 
@@ -4401,7 +4420,7 @@ 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.
@@ -5016,7 +5035,7 @@ 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
@@ -5124,6 +5143,24 @@ 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
 ---------------------
 
@@ -5475,7 +5512,7 @@ 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
@@ -6070,6 +6107,137 @@ writes to the CNTVCT_EL0 and CNTPCT_EL0 registers using the SET_ONE_REG
 interface. No error will be returned, but the resulting offset will not be
 applied.
 
+4.139 KVM_SET_USER_MEMORY_REGION2
+---------------------------------
+
+:Capability: KVM_CAP_USER_MEMORY2
+:Architectures: all
+:Type: vm ioctl
+:Parameters: struct kvm_userspace_memory_region2 (in)
+:Returns: 0 on success, -1 on error
+
+KVM_SET_USER_MEMORY_REGION2 is an extension to KVM_SET_USER_MEMORY_REGION that
+allows mapping guest_memfd memory into a guest.  All fields shared with
+KVM_SET_USER_MEMORY_REGION identically.  Userspace can set KVM_MEM_PRIVATE in
+flags to have KVM bind the memory region to a given guest_memfd range of
+[guest_memfd_offset, guest_memfd_offset + memory_size].  The target guest_memfd
+must point at a file created via KVM_CREATE_GUEST_MEMFD on the current VM, and
+the target range must not be bound to any other memory region.  All standard
+bounds checks apply (use common sense).
+
+::
+
+  struct kvm_userspace_memory_region2 {
+	__u32 slot;
+	__u32 flags;
+	__u64 guest_phys_addr;
+	__u64 memory_size; /* bytes */
+	__u64 userspace_addr; /* start of the userspace allocated memory */
+  __u64 guest_memfd_offset;
+	__u32 guest_memfd;
+	__u32 pad1;
+	__u64 pad2[14];
+  };
+
+A KVM_MEM_PRIVATE region _must_ have a valid guest_memfd (private memory) and
+userspace_addr (shared memory).  However, "valid" for userspace_addr simply
+means that the address itself must be a legal userspace address.  The backing
+mapping for userspace_addr is not required to be valid/populated at the time of
+KVM_SET_USER_MEMORY_REGION2, e.g. shared memory can be lazily mapped/allocated
+on-demand.
+
+When mapping a gfn into the guest, KVM selects shared vs. private, i.e consumes
+userspace_addr vs. guest_memfd, based on the gfn's KVM_MEMORY_ATTRIBUTE_PRIVATE
+state.  At VM creation time, all memory is shared, i.e. the PRIVATE attribute
+is '0' for all gfns.  Userspace can control whether memory is shared/private by
+toggling KVM_MEMORY_ATTRIBUTE_PRIVATE via KVM_SET_MEMORY_ATTRIBUTES as needed.
+
+4.140 KVM_SET_MEMORY_ATTRIBUTES
+-------------------------------
+
+:Capability: KVM_CAP_MEMORY_ATTRIBUTES
+:Architectures: x86
+:Type: vm ioctl
+:Parameters: struct kvm_memory_attributes(in)
+:Returns: 0 on success, <0 on error
+
+KVM_SET_MEMORY_ATTRIBUTES allows userspace to set memory attributes for a range
+of guest physical memory.
+
+::
+
+  struct kvm_memory_attributes {
+	__u64 address;
+	__u64 size;
+	__u64 attributes;
+	__u64 flags;
+  };
+
+  #define KVM_MEMORY_ATTRIBUTE_PRIVATE           (1ULL << 3)
+
+The address and size must be page aligned.  The supported attributes can be
+retrieved via ioctl(KVM_CHECK_EXTENSION) on KVM_CAP_MEMORY_ATTRIBUTES.  If
+executed on a VM, KVM_CAP_MEMORY_ATTRIBUTES precisely returns the attributes
+supported by that VM.  If executed at system scope, KVM_CAP_MEMORY_ATTRIBUTES
+returns all attributes supported by KVM.  The only attribute defined at this
+time is KVM_MEMORY_ATTRIBUTE_PRIVATE, which marks the associated gfn as being
+guest private memory.
+
+Note, there is no "get" API.  Userspace is responsible for explicitly tracking
+the state of a gfn/page as needed.
+
+The "flags" field is reserved for future extensions and must be '0'.
+
+4.141 KVM_CREATE_GUEST_MEMFD
+----------------------------
+
+:Capability: KVM_CAP_GUEST_MEMFD
+:Architectures: none
+:Type: vm ioctl
+:Parameters: struct struct kvm_create_guest_memfd(in)
+:Returns: 0 on success, <0 on error
+
+KVM_CREATE_GUEST_MEMFD creates an anonymous file and returns a file descriptor
+that refers to it.  guest_memfd files are roughly analogous to files created
+via memfd_create(), e.g. guest_memfd files live in RAM, have volatile storage,
+and are automatically released when the last reference is dropped.  Unlike
+"regular" memfd_create() files, guest_memfd files are bound to their owning
+virtual machine (see below), cannot be mapped, read, or written by userspace,
+and cannot be resized  (guest_memfd files do however support PUNCH_HOLE).
+
+::
+
+  struct kvm_create_guest_memfd {
+	__u64 size;
+	__u64 flags;
+	__u64 reserved[6];
+  };
+
+  #define KVM_GUEST_MEMFD_ALLOW_HUGEPAGE         (1ULL << 0)
+
+Conceptually, the inode backing a guest_memfd file represents physical memory,
+i.e. is coupled to the virtual machine as a thing, not to a "struct kvm".  The
+file itself, which is bound to a "struct kvm", is that instance's view of the
+underlying memory, e.g. effectively provides the translation of guest addresses
+to host memory.  This allows for use cases where multiple KVM structures are
+used to manage a single virtual machine, e.g. when performing intrahost
+migration of a virtual machine.
+
+KVM currently only supports mapping guest_memfd via KVM_SET_USER_MEMORY_REGION2,
+and more specifically via the guest_memfd and guest_memfd_offset fields in
+"struct kvm_userspace_memory_region2", where guest_memfd_offset is the offset
+into the guest_memfd instance.  For a given guest_memfd file, there can be at
+most one mapping per page, i.e. binding multiple memory regions to a single
+guest_memfd range is not allowed (any number of memory regions can be bound to
+a single guest_memfd file, but the bound ranges must not overlap).
+
+If KVM_GUEST_MEMFD_ALLOW_HUGEPAGE is set in flags, KVM will attempt to allocate
+and map hugepages for the guest_memfd file.  This is currently best effort.  If
+KVM_GUEST_MEMFD_ALLOW_HUGEPAGE is set, the size must be aligned to the maximum
+transparent hugepage size supported by the kernel
+
+See KVM_SET_USER_MEMORY_REGION2 for additional details.
+
 5. The kvm_run structure
 ========================
 
@@ -6702,6 +6870,30 @@ array field represents return values. The userspace should update the return
 values of SBI call before resuming the VCPU. For more details on RISC-V SBI
 spec refer, https://github.com/riscv/riscv-sbi-doc.
 
+::
+
+		/* KVM_EXIT_MEMORY_FAULT */
+		struct {
+  #define KVM_MEMORY_EXIT_FLAG_PRIVATE	(1ULL << 3)
+			__u64 flags;
+			__u64 gpa;
+			__u64 size;
+		} memory;
+
+KVM_EXIT_MEMORY_FAULT indicates the vCPU has encountered a memory fault that
+could not be resolved by KVM.  The 'gpa' and 'size' (in bytes) describe the
+guest physical address range [gpa, gpa + size) of the fault.  The 'flags' field
+describes properties of the faulting access that are likely pertinent:
+
+ - KVM_MEMORY_EXIT_FLAG_PRIVATE - When set, indicates the memory fault occurred
+   on a private memory access.  When clear, indicates the fault occurred on a
+   shared access.
+
+Note!  KVM_EXIT_MEMORY_FAULT is unique among all KVM exit reasons in that it
+accompanies a return code of '-1', not '0'!  errno will always be set to EFAULT
+or EHWPOISON when KVM exits with KVM_EXIT_MEMORY_FAULT, userspace should assume
+kvm_run.exit_reason is stale/undefined for all other error numbers.
+
 ::
 
     /* KVM_EXIT_NOTIFY */
@@ -7736,6 +7928,27 @@ This capability is aimed to mitigate the threat that malicious VMs can
 cause CPU stuck (due to event windows don't open up) and make the CPU
 unavailable to host or other VMs.
 
+7.34 KVM_CAP_MEMORY_FAULT_INFO
+------------------------------
+
+:Architectures: x86
+:Returns: Informational only, -EINVAL on direct KVM_ENABLE_CAP.
+
+The presence of this capability indicates that KVM_RUN will fill
+kvm_run.memory_fault if KVM cannot resolve a guest page fault VM-Exit, e.g. if
+there is a valid memslot but no backing VMA for the corresponding host virtual
+address.
+
+The information in kvm_run.memory_fault is valid if and only if KVM_RUN returns
+an error with errno=EFAULT or errno=EHWPOISON *and* kvm_run.exit_reason is set
+to KVM_EXIT_MEMORY_FAULT.
+
+Note: Userspaces which attempt to resolve memory faults so that they can retry
+KVM_RUN are encouraged to guard against repeatedly receiving the same
+error/annotated fault.
+
+See KVM_EXIT_MEMORY_FAULT for more information.
+
 8. Other capabilities.
 ======================
 
@@ -8474,6 +8687,19 @@ block sizes is exposed in KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES as a
 64-bit bitmap (each bit describing a block size). The default value is
 0, to disable the eager page splitting.
 
+8.41 KVM_CAP_VM_TYPES
+---------------------
+
+:Capability: KVM_CAP_MEMORY_ATTRIBUTES
+:Architectures: x86
+:Type: system ioctl
+
+This capability returns a bitmap of support VM types.  The 1-setting of bit @n
+means the VM type with value @n is supported.  Possible values of @n are::
+
+  #define KVM_X86_DEFAULT_VM	0
+  #define KVM_X86_SW_PROTECTED_VM	1
+
 9. Known KVM API problems
 =========================