kernel/linux.git/arch/powerpc/include/asm/kvm_host.h, branch linux-7.0.y

KVM: Drop kvm_arch_sync_events() now that all implementations are nops

2025-02-26T18:17:23+00:00

Remove kvm_arch_sync_events() now that x86 no longer uses it (no other arch has ever used it). No functional change intended. Signed-off-by: Sean Christopherson Acked-by: Claudio Imbrenda Reviewed-by: Bibo Mao Message-ID: <20250224235542.2562848-8-seanjc@google.com> Signed-off-by: Paolo Bonzini

powerpc/kvm: Add vpa latency counters to kvm_vcpu_arch

2024-11-19T03:11:21+00:00

Commit e1f288d2f9c69 ("KVM: PPC: Book3S HV nestedv2: Add support for reading VPA counters for pseries guests") introduced support for new Virtual Process Area(VPA) based software counters. These counters are useful when observing context switch latency of L1 <-> L2. It also added access to counters in lppaca, which is good enough to understand latency details per-cpu level. But to extend and aggregate per-process level(qemu) or per-pid/tid level(vcpu), these counters also needs to be added as part of kvm_vcpu_arch struct. Additional code added to update these new kvm_vcpu_arch variables in do_trace_nested_cs_time function. Signed-off-by: Kajol Jain Co-developed-by: Madhavan Srinivasan Signed-off-by: Madhavan Srinivasan Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/20241118114114.208964-3-kjain@linux.ibm.com

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

2024-07-20T19:41:03+00:00

Pull kvm updates from Paolo Bonzini: "ARM: - Initial infrastructure for shadow stage-2 MMUs, as part of nested virtualization enablement - Support for userspace changes to the guest CTR_EL0 value, enabling (in part) migration of VMs between heterogenous hardware - Fixes + improvements to pKVM's FF-A proxy, adding support for v1.1 of the protocol - FPSIMD/SVE support for nested, including merged trap configuration and exception routing - New command-line parameter to control the WFx trap behavior under KVM - Introduce kCFI hardening in the EL2 hypervisor - Fixes + cleanups for handling presence/absence of FEAT_TCRX - Miscellaneous fixes + documentation updates LoongArch: - Add paravirt steal time support - Add support for KVM_DIRTY_LOG_INITIALLY_SET - Add perf kvm-stat support for loongarch RISC-V: - Redirect AMO load/store access fault traps to guest - perf kvm stat support - Use guest files for IMSIC virtualization, when available s390: - Assortment of tiny fixes which are not time critical x86: - Fixes for Xen emulation - Add a global struct to consolidate tracking of host values, e.g. EFER - Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the effective APIC bus frequency, because TDX - Print the name of the APICv/AVIC inhibits in the relevant tracepoint - Clean up KVM's handling of vendor specific emulation to consistently act on "compatible with Intel/AMD", versus checking for a specific vendor - Drop MTRR virtualization, and instead always honor guest PAT on CPUs that support self-snoop - Update to the newfangled Intel CPU FMS infrastructure - Don't advertise IA32_PERF_GLOBAL_OVF_CTRL as an MSR-to-be-saved, as it reads '0' and writes from userspace are ignored - Misc cleanups x86 - MMU: - Small cleanups, renames and refactoring extracted from the upcoming Intel TDX support - Don't allocate kvm_mmu_page.shadowed_translation for shadow pages that can't hold leafs SPTEs - Unconditionally drop mmu_lock when allocating TDP MMU page tables for eager page splitting, to avoid stalling vCPUs when splitting huge pages - Bug the VM instead of simply warning if KVM tries to split a SPTE that is non-present or not-huge. KVM is guaranteed to end up in a broken state because the callers fully expect a valid SPTE, it's all but dangerous to let more MMU changes happen afterwards x86 - AMD: - Make per-CPU save_area allocations NUMA-aware - Force sev_es_host_save_area() to be inlined to avoid calling into an instrumentable function from noinstr code - Base support for running SEV-SNP guests. API-wise, this includes a new KVM_X86_SNP_VM type, encrypting/measure the initial image into guest memory, and finalizing it before launching it. Internally, there are some gmem/mmu hooks needed to prepare gmem-allocated pages before mapping them into guest private memory ranges This includes basic support for attestation guest requests, enough to say that KVM supports the GHCB 2.0 specification There is no support yet for loading into the firmware those signing keys to be used for attestation requests, and therefore no need yet for the host to provide certificate data for those keys. To support fetching certificate data from userspace, a new KVM exit type will be needed to handle fetching the certificate from userspace. An attempt to define a new KVM_EXIT_COCO / KVM_EXIT_COCO_REQ_CERTS exit type to handle this was introduced in v1 of this patchset, but is still being discussed by community, so for now this patchset only implements a stub version of SNP Extended Guest Requests that does not provide certificate data x86 - Intel: - Remove an unnecessary EPT TLB flush when enabling hardware - Fix a series of bugs that cause KVM to fail to detect nested pending posted interrupts as valid wake eents for a vCPU executing HLT in L2 (with HLT-exiting disable by L1) - KVM: x86: Suppress MMIO that is triggered during task switch emulation Explicitly suppress userspace emulated MMIO exits that are triggered when emulating a task switch as KVM doesn't support userspace MMIO during complex (multi-step) emulation Silently ignoring the exit request can result in the WARN_ON_ONCE(vcpu->mmio_needed) firing if KVM exits to userspace for some other reason prior to purging mmio_needed See commit 0dc902267cb3 ("KVM: x86: Suppress pending MMIO write exits if emulator detects exception") for more details on KVM's limitations with respect to emulated MMIO during complex emulator flows Generic: - Rename the AS_UNMOVABLE flag that was introduced for KVM to AS_INACCESSIBLE, because the special casing needed by these pages is not due to just unmovability (and in fact they are only unmovable because the CPU cannot access them) - New ioctl to populate the KVM page tables in advance, which is useful to mitigate KVM page faults during guest boot or after live migration. The code will also be used by TDX, but (probably) not through the ioctl - Enable halt poll shrinking by default, as Intel found it to be a clear win - Setup empty IRQ routing when creating a VM to avoid having to synchronize SRCU when creating a split IRQCHIP on x86 - Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag that arch code can use for hooking both sched_in() and sched_out() - Take the vCPU @id as an "unsigned long" instead of "u32" to avoid truncating a bogus value from userspace, e.g. to help userspace detect bugs - Mark a vCPU as preempted if and only if it's scheduled out while in the KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest memory when retrieving guest state during live migration blackout Selftests: - Remove dead code in the memslot modification stress test - Treat "branch instructions retired" as supported on all AMD Family 17h+ CPUs - Print the guest pseudo-RNG seed only when it changes, to avoid spamming the log for tests that create lots of VMs - Make the PMU counters test less flaky when counting LLC cache misses by doing CLFLUSH{OPT} in every loop iteration" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (227 commits) crypto: ccp: Add the SNP_VLEK_LOAD command KVM: x86/pmu: Add kvm_pmu_call() to simplify static calls of kvm_pmu_ops KVM: x86: Introduce kvm_x86_call() to simplify static calls of kvm_x86_ops KVM: x86: Replace static_call_cond() with static_call() KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event x86/sev: Move sev_guest.h into common SEV header KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event KVM: x86: Suppress MMIO that is triggered during task switch emulation KVM: x86/mmu: Clean up make_huge_page_split_spte() definition and intro KVM: x86/mmu: Bug the VM if KVM tries to split a !hugepage SPTE KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY KVM: x86: Implement kvm_arch_vcpu_pre_fault_memory() KVM: x86/mmu: Make kvm_mmu_do_page_fault() return mapped level KVM: x86/mmu: Account pf_{fixed,emulate,spurious} in callers of "do page fault" KVM: x86/mmu: Bump pf_taken stat only in the "real" page fault handler KVM: Add KVM_PRE_FAULT_MEMORY vcpu ioctl to pre-populate guest memory KVM: Document KVM_PRE_FAULT_MEMORY ioctl mm, virt: merge AS_UNMOVABLE and AS_INACCESSIBLE perf kvm: Add kvm-stat for loongarch64 LoongArch: KVM: Add PV steal time support in guest side ...

KVM: Delete the now unused kvm_arch_sched_in()

2024-06-11T21:18:45+00:00

Delete kvm_arch_sched_in() now that all implementations are nops. Reviewed-by: Bibo Mao Acked-by: Kai Huang Link: https://lore.kernel.org/r/20240522014013.1672962-5-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: PPC: Book3S HV: Add one-reg interface for HASHPKEYR register

2024-06-06T12:39:04+00:00

The patch adds a one-reg register identifier which can be used to read and set the virtual HASHPKEYR for the guest during enter/exit with KVM_REG_PPC_HASHPKEYR. The specific SPR KVM API documentation too updated. Signed-off-by: Shivaprasad G Bhat Signed-off-by: Michael Ellerman Link: https://msgid.link/171759285547.1480.12374595786792346073.stgit@linux.ibm.com

KVM: PPC: Book3S HV: Add one-reg interface for HASHKEYR register

2024-06-06T12:39:04+00:00

The patch adds a one-reg register identifier which can be used to read and set the virtual HASHKEYR for the guest during enter/exit with KVM_REG_PPC_HASHKEYR. The specific SPR KVM API documentation too updated. Signed-off-by: Shivaprasad G Bhat Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://msgid.link/171759283170.1480.12904332463112769129.stgit@linux.ibm.com

KVM: PPC: Book3S HV: Add one-reg interface for DEXCR register

2024-06-06T12:39:03+00:00

The patch adds a one-reg register identifier which can be used to read and set the DEXCR for the guest during enter/exit with KVM_REG_PPC_DEXCR. The specific SPR KVM API documentation too updated. Signed-off-by: Shivaprasad G Bhat Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://msgid.link/171759279613.1480.12873911783530175699.stgit@linux.ibm.com

Merge branch 'kvm-guestmemfd' into HEAD

2023-11-14T13:31:31+00:00

Introduce several new KVM uAPIs to ultimately create a guest-first memory subsystem within KVM, a.k.a. guest_memfd. Guest-first memory allows KVM to provide features, enhancements, and optimizations that are kludgly or outright impossible to implement in a generic memory subsystem. The core KVM ioctl() for guest_memfd is KVM_CREATE_GUEST_MEMFD, which similar to the generic memfd_create(), creates an anonymous file and returns a file descriptor that refers to it. Again like "regular" memfd files, guest_memfd files live in RAM, have volatile storage, and are automatically released when the last reference is dropped. The key differences between memfd files (and every other memory subystem) is that 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 convert a guest memory area between the shared and guest-private states. A second KVM ioctl(), KVM_SET_MEMORY_ATTRIBUTES, allows userspace to specify attributes for a given page of guest memory. In the long term, it will likely be extended to allow userspace to specify per-gfn RWX protections, including allowing memory to be writable in the guest without it also being writable in host userspace. The immediate and driving use case for guest_memfd are Confidential (CoCo) VMs, specifically AMD's SEV-SNP, Intel's TDX, and KVM's own pKVM. For such use cases, being able to map memory into KVM guests without requiring said memory to be mapped into the host is a hard requirement. While SEV+ and TDX prevent untrusted software from reading guest private data by encrypting guest memory, pKVM provides confidentiality and integrity *without* relying on memory encryption. In addition, with SEV-SNP and especially TDX, accessing guest private memory can be fatal to the host, i.e. KVM must be prevent host userspace from accessing guest memory irrespective of hardware behavior. Long term, guest_memfd may be useful for use cases beyond CoCo VMs, for example hardening userspace against unintentional accesses to guest memory. As mentioned earlier, KVM's ABI uses userspace VMA protections to define the allow guest protection (with an exception granted to mapping guest memory executable), and similarly KVM currently requires the guest mapping size to be a strict subset of the host userspace mapping size. Decoupling the mappings sizes would allow userspace to precisely map only what is needed and with the required permissions, without impacting guest performance. A guest-first memory subsystem also provides clearer line of sight to things like a dedicated memory pool (for slice-of-hardware VMs) and elimination of "struct page" (for offload setups where userspace _never_ needs to DMA from or into guest memory). guest_memfd is the result of 3+ years of development and exploration; taking on memory management responsibilities in KVM was not the first, second, or even third choice for supporting CoCo VMs. But after many failed attempts to avoid KVM-specific backing memory, and looking at where things ended up, it is quite clear that of all approaches tried, guest_memfd is the simplest, most robust, and most extensible, and the right thing to do for KVM and the kernel at-large. The "development cycle" for this version is going to be very short; ideally, next week I will merge it as is in kvm/next, taking this through the KVM tree for 6.8 immediately after the end of the merge window. The series is still based on 6.6 (plus KVM changes for 6.7) so it will require a small fixup for changes to get_file_rcu() introduced in 6.7 by commit 0ede61d8589c ("file: convert to SLAB_TYPESAFE_BY_RCU"). The fixup will be done as part of the merge commit, and most of the text above will become the commit message for the merge. Pending post-merge work includes: - hugepage support - looking into using the restrictedmem framework for guest memory - introducing a testing mechanism to poison memory, possibly using the same memory attributes introduced here - SNP and TDX support There are two non-KVM patches buried in the middle of this series: fs: Rename anon_inode_getfile_secure() and anon_inode_getfd_secure() mm: Add AS_UNMOVABLE to mark mapping as completely unmovable The first is small and mostly suggested-by Christian Brauner; the second a bit less so but it was written by an mm person (Vlastimil Babka).

KVM: Convert KVM_ARCH_WANT_MMU_NOTIFIER to CONFIG_KVM_GENERIC_MMU_NOTIFIER

2023-11-13T10:29:09+00:00

Convert KVM_ARCH_WANT_MMU_NOTIFIER into a Kconfig and select it where appropriate to effectively maintain existing behavior. Using a proper Kconfig will simplify building more functionality on top of KVM's mmu_notifier infrastructure. Add a forward declaration of kvm_gfn_range to kvm_types.h so that including arch/powerpc/include/asm/kvm_ppc.h's with CONFIG_KVM=n doesn't generate warnings due to kvm_gfn_range being undeclared. PPC defines hooks for PR vs. HV without guarding them via #ifdeffery, e.g. bool (*unmap_gfn_range)(struct kvm *kvm, struct kvm_gfn_range *range); bool (*age_gfn)(struct kvm *kvm, struct kvm_gfn_range *range); bool (*test_age_gfn)(struct kvm *kvm, struct kvm_gfn_range *range); bool (*set_spte_gfn)(struct kvm *kvm, struct kvm_gfn_range *range); Alternatively, PPC could forward declare kvm_gfn_range, but there's no good reason not to define it in common KVM. Acked-by: Anup Patel Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Message-Id: <20231027182217.3615211-8-seanjc@google.com> Signed-off-by: Paolo Bonzini

KVM: PPC: Add support for nestedv2 guests

2023-09-14T12:04:24+00:00

A series of hcalls have been added to the PAPR which allow a regular guest partition to create and manage guest partitions of its own. KVM already had an interface that allowed this on powernv platforms. This existing interface will now be called "nestedv1". The newly added PAPR interface will be called "nestedv2". PHYP will support the nestedv2 interface. At this time the host side of the nestedv2 interface has not been implemented on powernv but there is no technical reason why it could not be added. The nestedv1 interface is still supported. Add support to KVM to utilize these hcalls to enable running nested guests as a pseries guest on PHYP. Overview of the new hcall usage: - L1 and L0 negotiate capabilities with H_GUEST_{G,S}ET_CAPABILITIES() - L1 requests the L0 create a L2 with H_GUEST_CREATE() and receives a handle to use in future hcalls - L1 requests the L0 create a L2 vCPU with H_GUEST_CREATE_VCPU() - L1 sets up the L2 using H_GUEST_SET and the H_GUEST_VCPU_RUN input buffer - L1 requests the L0 runs the L2 vCPU using H_GUEST_VCPU_RUN() - L2 returns to L1 with an exit reason and L1 reads the H_GUEST_VCPU_RUN output buffer populated by the L0 - L1 handles the exit using H_GET_STATE if necessary - L1 reruns L2 vCPU with H_GUEST_VCPU_RUN - L1 frees the L2 in the L0 with H_GUEST_DELETE() Support for the new API is determined by trying H_GUEST_GET_CAPABILITIES. On a successful return, use the nestedv2 interface. Use the vcpu register state setters for tracking modified guest state elements and copy the thread wide values into the H_GUEST_VCPU_RUN input buffer immediately before running a L2. The guest wide elements can not be added to the input buffer so send them with a separate H_GUEST_SET call if necessary. Make the vcpu register getter load the corresponding value from the real host with H_GUEST_GET. To avoid unnecessarily calling H_GUEST_GET, track which values have already been loaded between H_GUEST_VCPU_RUN calls. If an element is present in the H_GUEST_VCPU_RUN output buffer it also does not need to be loaded again. Tested-by: Sachin Sant Signed-off-by: Vaibhav Jain Signed-off-by: Gautam Menghani Signed-off-by: Kautuk Consul Signed-off-by: Amit Machhiwal Signed-off-by: Jordan Niethe Signed-off-by: Michael Ellerman Link: https://msgid.link/20230914030600.16993-11-jniethe5@gmail.com