Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "Generic:

   - Use memdup_array_user() to harden against overflow.

   - Unconditionally advertise KVM_CAP_DEVICE_CTRL for all
     architectures.

   - Clean up Kconfigs that all KVM architectures were selecting

   - New functionality around "guest_memfd", a new userspace API that
     creates an anonymous file and returns a file descriptor that refers
     to it. guest_memfd files are bound to their owning virtual machine,
     cannot be mapped, read, or written by userspace, and cannot be
     resized. guest_memfd files do however support PUNCH_HOLE, which can
     be used to switch a memory area between guest_memfd and regular
     anonymous memory.

   - New ioctl KVM_SET_MEMORY_ATTRIBUTES allowing userspace to specify
     per-page attributes for a given page of guest memory; right now the
     only attribute is whether the guest expects to access memory via
     guest_memfd or not, which in Confidential SVMs backed by SEV-SNP,
     TDX or ARM64 pKVM is checked by firmware or hypervisor that
     guarantees confidentiality (AMD PSP, Intel TDX module, or EL2 in
     the case of pKVM).

  x86:

   - Support for "software-protected VMs" that can use the new
     guest_memfd and page attributes infrastructure. This is mostly
     useful for testing, since there is no pKVM-like infrastructure to
     provide a meaningfully reduced TCB.

   - Fix a relatively benign off-by-one error when splitting huge pages
     during CLEAR_DIRTY_LOG.

   - Fix a bug where KVM could incorrectly test-and-clear dirty bits in
     non-leaf TDP MMU SPTEs if a racing thread replaces a huge SPTE with
     a non-huge SPTE.

   - Use more generic lockdep assertions in paths that don't actually
     care about whether the caller is a reader or a writer.

   - let Xen guests opt out of having PV clock reported as "based on a
     stable TSC", because some of them don't expect the "TSC stable" bit
     (added to the pvclock ABI by KVM, but never set by Xen) to be set.

   - Revert a bogus, made-up nested SVM consistency check for
     TLB_CONTROL.

   - Advertise flush-by-ASID support for nSVM unconditionally, as KVM
     always flushes on nested transitions, i.e. always satisfies flush
     requests. This allows running bleeding edge versions of VMware
     Workstation on top of KVM.

   - Sanity check that the CPU supports flush-by-ASID when enabling SEV
     support.

   - On AMD machines with vNMI, always rely on hardware instead of
     intercepting IRET in some cases to detect unmasking of NMIs

   - Support for virtualizing Linear Address Masking (LAM)

   - Fix a variety of vPMU bugs where KVM fail to stop/reset counters
     and other state prior to refreshing the vPMU model.

   - Fix a double-overflow PMU bug by tracking emulated counter events
     using a dedicated field instead of snapshotting the "previous"
     counter. If the hardware PMC count triggers overflow that is
     recognized in the same VM-Exit that KVM manually bumps an event
     count, KVM would pend PMIs for both the hardware-triggered overflow
     and for KVM-triggered overflow.

   - Turn off KVM_WERROR by default for all configs so that it's not
     inadvertantly enabled by non-KVM developers, which can be
     problematic for subsystems that require no regressions for W=1
     builds.

   - Advertise all of the host-supported CPUID bits that enumerate
     IA32_SPEC_CTRL "features".

   - Don't force a masterclock update when a vCPU synchronizes to the
     current TSC generation, as updating the masterclock can cause
     kvmclock's time to "jump" unexpectedly, e.g. when userspace
     hotplugs a pre-created vCPU.

   - Use RIP-relative address to read kvm_rebooting in the VM-Enter
     fault paths, partly as a super minor optimization, but mostly to
     make KVM play nice with position independent executable builds.

   - Guard KVM-on-HyperV's range-based TLB flush hooks with an #ifdef on
     CONFIG_HYPERV as a minor optimization, and to self-document the
     code.

   - Add CONFIG_KVM_HYPERV to allow disabling KVM support for HyperV
     "emulation" at build time.

  ARM64:

   - LPA2 support, adding 52bit IPA/PA capability for 4kB and 16kB base
     granule sizes. Branch shared with the arm64 tree.

   - Large Fine-Grained Trap rework, bringing some sanity to the
     feature, although there is more to come. This comes with a prefix
     branch shared with the arm64 tree.

   - Some additional Nested Virtualization groundwork, mostly
     introducing the NV2 VNCR support and retargetting the NV support to
     that version of the architecture.

   - A small set of vgic fixes and associated cleanups.

  Loongarch:

   - Optimization for memslot hugepage checking

   - Cleanup and fix some HW/SW timer issues

   - Add LSX/LASX (128bit/256bit SIMD) support

  RISC-V:

   - KVM_GET_REG_LIST improvement for vector registers

   - Generate ISA extension reg_list using macros in get-reg-list
     selftest

   - Support for reporting steal time along with selftest

  s390:

   - Bugfixes

  Selftests:

   - Fix an annoying goof where the NX hugepage test prints out garbage
     instead of the magic token needed to run the test.

   - Fix build errors when a header is delete/moved due to a missing
     flag in the Makefile.

   - Detect if KVM bugged/killed a selftest's VM and print out a helpful
     message instead of complaining that a random ioctl() failed.

   - Annotate the guest printf/assert helpers with __printf(), and fix
     the various bugs that were lurking due to lack of said annotation"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (185 commits)
  x86/kvm: Do not try to disable kvmclock if it was not enabled
  KVM: x86: add missing "depends on KVM"
  KVM: fix direction of dependency on MMU notifiers
  KVM: introduce CONFIG_KVM_COMMON
  KVM: arm64: Add missing memory barriers when switching to pKVM's hyp pgd
  KVM: arm64: vgic-its: Avoid potential UAF in LPI translation cache
  RISC-V: KVM: selftests: Add get-reg-list test for STA registers
  RISC-V: KVM: selftests: Add steal_time test support
  RISC-V: KVM: selftests: Add guest_sbi_probe_extension
  RISC-V: KVM: selftests: Move sbi_ecall to processor.c
  RISC-V: KVM: Implement SBI STA extension
  RISC-V: KVM: Add support for SBI STA registers
  RISC-V: KVM: Add support for SBI extension registers
  RISC-V: KVM: Add SBI STA info to vcpu_arch
  RISC-V: KVM: Add steal-update vcpu request
  RISC-V: KVM: Add SBI STA extension skeleton
  RISC-V: paravirt: Implement steal-time support
  RISC-V: Add SBI STA extension definitions
  RISC-V: paravirt: Add skeleton for pv-time support
  RISC-V: KVM: Fix indentation in kvm_riscv_vcpu_set_reg_csr()
  ...

1 files changed, 83 insertions, 41 deletions

diff --git a/arch/loongarch/kvm/mmu.c b/arch/loongarch/kvm/mmu.c
index 80480df5f550..915f17527893 100644
--- a/arch/loongarch/kvm/mmu.c
+++ b/arch/loongarch/kvm/mmu.c
@@ -13,6 +13,16 @@
 #include <asm/tlb.h>
 #include <asm/kvm_mmu.h>
 
+static inline bool kvm_hugepage_capable(struct kvm_memory_slot *slot)
+{
+	return slot->arch.flags & KVM_MEM_HUGEPAGE_CAPABLE;
+}
+
+static inline bool kvm_hugepage_incapable(struct kvm_memory_slot *slot)
+{
+	return slot->arch.flags & KVM_MEM_HUGEPAGE_INCAPABLE;
+}
+
 static inline void kvm_ptw_prepare(struct kvm *kvm, kvm_ptw_ctx *ctx)
 {
 	ctx->level = kvm->arch.root_level;
@@ -365,6 +375,69 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
 	kvm_ptw_top(kvm->arch.pgd, start << PAGE_SHIFT, end << PAGE_SHIFT, &ctx);
 }
 
+int kvm_arch_prepare_memory_region(struct kvm *kvm, const struct kvm_memory_slot *old,
+				   struct kvm_memory_slot *new, enum kvm_mr_change change)
+{
+	gpa_t gpa_start;
+	hva_t hva_start;
+	size_t size, gpa_offset, hva_offset;
+
+	if ((change != KVM_MR_MOVE) && (change != KVM_MR_CREATE))
+		return 0;
+	/*
+	 * Prevent userspace from creating a memory region outside of the
+	 * VM GPA address space
+	 */
+	if ((new->base_gfn + new->npages) > (kvm->arch.gpa_size >> PAGE_SHIFT))
+		return -ENOMEM;
+
+	new->arch.flags = 0;
+	size = new->npages * PAGE_SIZE;
+	gpa_start = new->base_gfn << PAGE_SHIFT;
+	hva_start = new->userspace_addr;
+	if (IS_ALIGNED(size, PMD_SIZE) && IS_ALIGNED(gpa_start, PMD_SIZE)
+			&& IS_ALIGNED(hva_start, PMD_SIZE))
+		new->arch.flags |= KVM_MEM_HUGEPAGE_CAPABLE;
+	else {
+		/*
+		 * Pages belonging to memslots that don't have the same
+		 * alignment within a PMD for userspace and GPA cannot be
+		 * mapped with PMD entries, because we'll end up mapping
+		 * the wrong pages.
+		 *
+		 * Consider a layout like the following:
+		 *
+		 *    memslot->userspace_addr:
+		 *    +-----+--------------------+--------------------+---+
+		 *    |abcde|fgh  Stage-1 block  |    Stage-1 block tv|xyz|
+		 *    +-----+--------------------+--------------------+---+
+		 *
+		 *    memslot->base_gfn << PAGE_SIZE:
+		 *      +---+--------------------+--------------------+-----+
+		 *      |abc|def  Stage-2 block  |    Stage-2 block   |tvxyz|
+		 *      +---+--------------------+--------------------+-----+
+		 *
+		 * If we create those stage-2 blocks, we'll end up with this
+		 * incorrect mapping:
+		 *   d -> f
+		 *   e -> g
+		 *   f -> h
+		 */
+		gpa_offset = gpa_start & (PMD_SIZE - 1);
+		hva_offset = hva_start & (PMD_SIZE - 1);
+		if (gpa_offset != hva_offset) {
+			new->arch.flags |= KVM_MEM_HUGEPAGE_INCAPABLE;
+		} else {
+			if (gpa_offset == 0)
+				gpa_offset = PMD_SIZE;
+			if ((size + gpa_offset) < (PMD_SIZE * 2))
+				new->arch.flags |= KVM_MEM_HUGEPAGE_INCAPABLE;
+		}
+	}
+
+	return 0;
+}
+
 void kvm_arch_commit_memory_region(struct kvm *kvm,
 				   struct kvm_memory_slot *old,
 				   const struct kvm_memory_slot *new,
@@ -562,47 +635,23 @@ out:
 }
 
 static bool fault_supports_huge_mapping(struct kvm_memory_slot *memslot,
-				unsigned long hva, unsigned long map_size, bool write)
+				unsigned long hva, bool write)
 {
-	size_t size;
-	gpa_t gpa_start;
-	hva_t uaddr_start, uaddr_end;
+	hva_t start, end;
 
 	/* Disable dirty logging on HugePages */
 	if (kvm_slot_dirty_track_enabled(memslot) && write)
 		return false;
 
-	size = memslot->npages * PAGE_SIZE;
-	gpa_start = memslot->base_gfn << PAGE_SHIFT;
-	uaddr_start = memslot->userspace_addr;
-	uaddr_end = uaddr_start + size;
+	if (kvm_hugepage_capable(memslot))
+		return true;
 
-	/*
-	 * Pages belonging to memslots that don't have the same alignment
-	 * within a PMD for userspace and GPA cannot be mapped with stage-2
-	 * PMD entries, because we'll end up mapping the wrong pages.
-	 *
-	 * Consider a layout like the following:
-	 *
-	 *    memslot->userspace_addr:
-	 *    +-----+--------------------+--------------------+---+
-	 *    |abcde|fgh  Stage-1 block  |    Stage-1 block tv|xyz|
-	 *    +-----+--------------------+--------------------+---+
-	 *
-	 *    memslot->base_gfn << PAGE_SIZE:
-	 *      +---+--------------------+--------------------+-----+
-	 *      |abc|def  Stage-2 block  |    Stage-2 block   |tvxyz|
-	 *      +---+--------------------+--------------------+-----+
-	 *
-	 * If we create those stage-2 blocks, we'll end up with this incorrect
-	 * mapping:
-	 *   d -> f
-	 *   e -> g
-	 *   f -> h
-	 */
-	if ((gpa_start & (map_size - 1)) != (uaddr_start & (map_size - 1)))
+	if (kvm_hugepage_incapable(memslot))
 		return false;
 
+	start = memslot->userspace_addr;
+	end = start + memslot->npages * PAGE_SIZE;
+
 	/*
 	 * Next, let's make sure we're not trying to map anything not covered
 	 * by the memslot. This means we have to prohibit block size mappings
@@ -615,8 +664,7 @@ static bool fault_supports_huge_mapping(struct kvm_memory_slot *memslot,
 	 * userspace_addr or the base_gfn, as both are equally aligned (per
 	 * the check above) and equally sized.
 	 */
-	return (hva & ~(map_size - 1)) >= uaddr_start &&
-		(hva & ~(map_size - 1)) + map_size <= uaddr_end;
+	return (hva >= ALIGN(start, PMD_SIZE)) && (hva < ALIGN_DOWN(end, PMD_SIZE));
 }
 
 /*
@@ -842,7 +890,7 @@ retry:
 
 	/* Disable dirty logging on HugePages */
 	level = 0;
-	if (!fault_supports_huge_mapping(memslot, hva, PMD_SIZE, write)) {
+	if (!fault_supports_huge_mapping(memslot, hva, write)) {
 		level = 0;
 	} else {
 		level = host_pfn_mapping_level(kvm, gfn, memslot);
@@ -901,12 +949,6 @@ void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
 {
 }
 
-int kvm_arch_prepare_memory_region(struct kvm *kvm, const struct kvm_memory_slot *old,
-				   struct kvm_memory_slot *new, enum kvm_mr_change change)
-{
-	return 0;
-}
-
 void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
 					const struct kvm_memory_slot *memslot)
 {