KVM cleanups for 6.10:

- Misc cleanups extracted from the "exit on missing userspace mapping" series,
    which has been put on hold in anticipation of a "KVM Userfault" approach,
    which should provide a superset of functionality.
 
  - Remove kvm_make_all_cpus_request_except(), which got added to hack around an
    AVIC bug, and then became dead code when a more robust fix came along.
 
  - Fix a goof in the KVM_CREATE_GUEST_MEMFD documentation.
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Merge tag 'kvm-x86-generic-6.10' of https://github.com/kvm-x86/linux into HEAD

KVM cleanups for 6.10:

 - Misc cleanups extracted from the "exit on missing userspace mapping" series,
   which has been put on hold in anticipation of a "KVM Userfault" approach,
   which should provide a superset of functionality.

 - Remove kvm_make_all_cpus_request_except(), which got added to hack around an
   AVIC bug, and then became dead code when a more robust fix came along.

 - Fix a goof in the KVM_CREATE_GUEST_MEMFD documentation.

Documentation/virt/kvm/api.rst

@@ -6316,7 +6316,7 @@ The "flags" field is reserved for future extensions and must be '0'.
 :Architectures: none
 :Type: vm ioctl
 :Parameters: struct kvm_create_guest_memfd(in)
-:Returns: 0 on success, <0 on error
+:Returns: A file descriptor 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

include/linux/kvm_host.h

@@ -193,8 +193,6 @@ static inline bool is_error_page(struct page *page)
 bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
 				 unsigned long *vcpu_bitmap);
 bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req);
-bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req,
-				      struct kvm_vcpu *except);
 
 #define KVM_USERSPACE_IRQ_SOURCE_ID		0
 #define KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID	1

virt/kvm/kvm_main.c

@@ -311,8 +311,7 @@ bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
 	return called;
 }
 
-bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req,
+bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
-				      struct kvm_vcpu *except)
 {
 	struct kvm_vcpu *vcpu;
 	struct cpumask *cpus;
@@ -325,22 +324,14 @@ bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req,
 	cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask);
 	cpumask_clear(cpus);
 
-	kvm_for_each_vcpu(i, vcpu, kvm) {
+	kvm_for_each_vcpu(i, vcpu, kvm)
-		if (vcpu == except)
-			continue;
 		kvm_make_vcpu_request(vcpu, req, cpus, me);
-	}
 
 	called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT));
 	put_cpu();
 
 	return called;
 }
-
-bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
-{
-	return kvm_make_all_cpus_request_except(kvm, req, NULL);
-}
 EXPORT_SYMBOL_GPL(kvm_make_all_cpus_request);
 
 void kvm_flush_remote_tlbs(struct kvm *kvm)
@@ -2932,7 +2923,7 @@ out:
 /*
  * Pin guest page in memory and return its pfn.
  * @addr: host virtual address which maps memory to the guest
- * @atomic: whether this function can sleep
+ * @atomic: whether this function is forbidden from sleeping
  * @interruptible: whether the process can be interrupted by non-fatal signals
  * @async: whether this function need to wait IO complete if the
  *         host page is not in the memory
@@ -3004,16 +2995,12 @@ kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn,
 	if (hva)
 		*hva = addr;
 
-	if (addr == KVM_HVA_ERR_RO_BAD) {
-		if (writable)
-			*writable = false;
-		return KVM_PFN_ERR_RO_FAULT;
-	}
-
 	if (kvm_is_error_hva(addr)) {
 		if (writable)
 			*writable = false;
-		return KVM_PFN_NOSLOT;
+
+		return addr == KVM_HVA_ERR_RO_BAD ? KVM_PFN_ERR_RO_FAULT :
+						    KVM_PFN_NOSLOT;
 	}
 
 	/* Do not map writable pfn in the readonly memslot. */
@@ -3277,6 +3264,7 @@ static int next_segment(unsigned long len, int offset)
 		return len;
 }
 
+/* Copy @len bytes from guest memory at '(@gfn * PAGE_SIZE) + @offset' to @data */
 static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn,
 				 void *data, int offset, int len)
 {
@@ -3378,6 +3366,7 @@ int kvm_vcpu_read_guest_atomic(struct kvm_vcpu *vcpu, gpa_t gpa,
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_atomic);
 
+/* Copy @len bytes from @data into guest memory at '(@gfn * PAGE_SIZE) + @offset' */
 static int __kvm_write_guest_page(struct kvm *kvm,
 				  struct kvm_memory_slot *memslot, gfn_t gfn,
 			          const void *data, int offset, int len)