linux.git/arch/s390/kvm, branch master

KVM: s390: Change virtual to physical address access in diag 0x258 handler

2024-10-10T13:31:55+00:00

The parameters for the diag 0x258 are real addresses, not virtual, but
KVM was using them as virtual addresses. This only happened to work, since
the Linux kernel as a guest used to have a 1:1 mapping for physical vs
virtual addresses.

Fix KVM so that it correctly uses the addresses as real addresses.

Cc: stable@vger.kernel.org
Fixes: 8ae04b8f500b ("KVM: s390: Guest's memory access functions get access registers")
Suggested-by: Vasily Gorbik 
Signed-off-by: Michael Mueller 
Signed-off-by: Nico Boehr 
Reviewed-by: Christian Borntraeger 
Reviewed-by: Heiko Carstens 
Link: https://lore.kernel.org/r/20240917151904.74314-3-nrb@linux.ibm.com
Acked-by: Janosch Frank 
Signed-off-by: Heiko Carstens

KVM: s390: gaccess: Check if guest address is in memslot

2024-10-10T13:31:55+00:00

Previously, access_guest_page() did not check whether the given guest
address is inside of a memslot. This is not a problem, since
kvm_write_guest_page/kvm_read_guest_page return -EFAULT in this case.

However, -EFAULT is also returned when copy_to/from_user fails.

When emulating a guest instruction, the address being outside a memslot
usually means that an addressing exception should be injected into the
guest.

Failure in copy_to/from_user however indicates that something is wrong
in userspace and hence should be handled there.

To be able to distinguish these two cases, return PGM_ADDRESSING in
access_guest_page() when the guest address is outside guest memory. In
access_guest_real(), populate vcpu->arch.pgm.code such that
kvm_s390_inject_prog_cond() can be used in the caller for injecting into
the guest (if applicable).

Since this adds a new return value to access_guest_page(), we need to make
sure that other callers are not confused by the new positive return value.

There are the following users of access_guest_page():
- access_guest_with_key() does the checking itself (in
  guest_range_to_gpas()), so this case should never happen. Even if, the
  handling is set up properly.
- access_guest_real() just passes the return code to its callers, which
  are:
    - read_guest_real() - see below
    - write_guest_real() - see below

There are the following users of read_guest_real():
- ar_translation() in gaccess.c which already returns PGM_*
- setup_apcb10(), setup_apcb00(), setup_apcb11() in vsie.c which always
  return -EFAULT on read_guest_read() nonzero return - no change
- shadow_crycb(), handle_stfle() always present this as validity, this
  could be handled better but doesn't change current behaviour - no change

There are the following users of write_guest_real():
- kvm_s390_store_status_unloaded() always returns -EFAULT on
  write_guest_real() failure.

Fixes: 2293897805c2 ("KVM: s390: add architecture compliant guest access functions")
Cc: stable@vger.kernel.org
Signed-off-by: Nico Boehr 
Reviewed-by: Heiko Carstens 
Link: https://lore.kernel.org/r/20240917151904.74314-2-nrb@linux.ibm.com
Acked-by: Janosch Frank 
Signed-off-by: Heiko Carstens

KVM: s390: Fix SORTL and DFLTCC instruction format error in __insn32_query

2024-08-19T07:51:14+00:00

The __insn32_query() function incorrectly uses the RRF instruction format
for both the SORTL (RRE format) and DFLTCC (RRF format) instructions.
To fix this issue, add separate query functions for SORTL and DFLTCC that
use the appropriate instruction formats.

Additionally pass the query operand as a pointer to the entire array
of 32 elements to slightly optimize performance and readability.

Fixes: d668139718a9 ("KVM: s390: provide query function for instructions returning 32 byte")
Suggested-by: Heiko Carstens 
Reviewed-by: Juergen Christ 
Signed-off-by: Hariharan Mari 
Signed-off-by: Janosch Frank

KVM: s390: fix validity interception issue when gisa is switched off

2024-08-06T06:33:18+00:00

We might run into a SIE validity if gisa has been disabled either via using
kernel parameter "kvm.use_gisa=0" or by setting the related sysfs
attribute to N (echo N >/sys/module/kvm/parameters/use_gisa).

The validity is caused by an invalid value in the SIE control block's
gisa designation. That happens because we pass the uninitialized gisa
origin to virt_to_phys() before writing it to the gisa designation.

To fix this we return 0 in kvm_s390_get_gisa_desc() if the origin is 0.
kvm_s390_get_gisa_desc() is used to determine which gisa designation to
set in the SIE control block. A value of 0 in the gisa designation disables
gisa usage.

The issue surfaces in the host kernel with the following kernel message as
soon a new kvm guest start is attemted.

kvm: unhandled validity intercept 0x1011
WARNING: CPU: 0 PID: 781237 at arch/s390/kvm/intercept.c:101 kvm_handle_sie_intercept+0x42e/0x4d0 [kvm]
Modules linked in: vhost_net tap tun xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT xt_tcpudp nft_compat x_tables nf_nat_tftp nf_conntrack_tftp vfio_pci_core irqbypass vhost_vsock vmw_vsock_virtio_transport_common vsock vhost vhost_iotlb kvm nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables sunrpc mlx5_ib ib_uverbs ib_core mlx5_core uvdevice s390_trng eadm_sch vfio_ccw zcrypt_cex4 mdev vfio_iommu_type1 vfio sch_fq_codel drm i2c_core loop drm_panel_orientation_quirks configfs nfnetlink lcs ctcm fsm dm_service_time ghash_s390 prng chacha_s390 libchacha aes_s390 des_s390 libdes sha3_512_s390 sha3_256_s390 sha512_s390 sha256_s390 sha1_s390 sha_common dm_mirror dm_region_hash dm_log zfcp scsi_transport_fc scsi_dh_rdac scsi_dh_emc scsi_dh_alua pkey zcrypt dm_multipath rng_core autofs4 [last unloaded: vfio_pci]
CPU: 0 PID: 781237 Comm: CPU 0/KVM Not tainted 6.10.0-08682-gcad9f11498ea #6
Hardware name: IBM 3931 A01 701 (LPAR)
Krnl PSW : 0704c00180000000 000003d93deb0122 (kvm_handle_sie_intercept+0x432/0x4d0 [kvm])
           R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3
Krnl GPRS: 000003d900000027 000003d900000023 0000000000000028 000002cd00000000
           000002d063a00900 00000359c6daf708 00000000000bebb5 0000000000001eff
           000002cfd82e9000 000002cfd80bc000 0000000000001011 000003d93deda412
           000003ff8962df98 000003d93de77ce0 000003d93deb011e 00000359c6daf960
Krnl Code: 000003d93deb0112: c020fffe7259	larl	%r2,000003d93de7e5c4
           000003d93deb0118: c0e53fa8beac	brasl	%r14,000003d9bd3c7e70
          #000003d93deb011e: af000000		mc	0,0
          >000003d93deb0122: a728ffea		lhi	%r2,-22
           000003d93deb0126: a7f4fe24		brc	15,000003d93deafd6e
           000003d93deb012a: 9101f0b0		tm	176(%r15),1
           000003d93deb012e: a774fe48		brc	7,000003d93deafdbe
           000003d93deb0132: 40a0f0ae		sth	%r10,174(%r15)
Call Trace:
 [<000003d93deb0122>] kvm_handle_sie_intercept+0x432/0x4d0 [kvm]
([<000003d93deb011e>] kvm_handle_sie_intercept+0x42e/0x4d0 [kvm])
 [<000003d93deacc10>] vcpu_post_run+0x1d0/0x3b0 [kvm]
 [<000003d93deaceda>] __vcpu_run+0xea/0x2d0 [kvm]
 [<000003d93dead9da>] kvm_arch_vcpu_ioctl_run+0x16a/0x430 [kvm]
 [<000003d93de93ee0>] kvm_vcpu_ioctl+0x190/0x7c0 [kvm]
 [<000003d9bd728b4e>] vfs_ioctl+0x2e/0x70
 [<000003d9bd72a092>] __s390x_sys_ioctl+0xc2/0xd0
 [<000003d9be0e9222>] __do_syscall+0x1f2/0x2e0
 [<000003d9be0f9a90>] system_call+0x70/0x98
Last Breaking-Event-Address:
 [<000003d9bd3c7f58>] __warn_printk+0xe8/0xf0

Cc: stable@vger.kernel.org
Reported-by: Christian Borntraeger 
Fixes: fe0ef0030463 ("KVM: s390: sort out physical vs virtual pointers usage")
Signed-off-by: Michael Mueller 
Tested-by: Christian Borntraeger 
Reviewed-by: Janosch Frank 
Link: https://lore.kernel.org/r/20240801123109.2782155-1-mimu@linux.ibm.com
Message-ID: <20240801123109.2782155-1-mimu@linux.ibm.com>
Signed-off-by: Janosch Frank

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
  ...

Merge tag 's390-6.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2024-07-18T22:41:45+00:00

Pull s390 updates from Vasily Gorbik:

 - Remove restrictions on PAI NNPA and crypto counters, enabling
   concurrent per-task and system-wide sampling and counting events

 - Switch to GENERIC_CPU_DEVICES by setting up the CPU present mask in
   the architecture code and letting the generic code handle CPU
   bring-up

 - Add support for the diag204 busy indication facility to prevent
   undesirable blocking during hypervisor logical CPU utilization
   queries. Implement results caching

 - Improve the handling of Store Data SCLP events by suppressing
   unnecessary warning, preventing buffer release in I/O during
   failures, and adding timeout handling for Store Data requests to
   address potential firmware issues

 - Provide optimized __arch_hweight*() implementations

 - Remove the unnecessary CPU KOBJ_CHANGE uevents generated during
   topology updates, as they are unused and also not present on other
   architectures

 - Cleanup atomic_ops, optimize __atomic_set() for small values and
   __atomic_cmpxchg_bool() for compilers supporting flag output
   constraint

 - Couple of cleanups for KVM:
     - Move and improve KVM struct definitions for DAT tables from
       gaccess.c to a new header
     - Pass the asce as parameter to sie64a()

 - Make the crdte() and cspg() page table handling wrappers return a
   boolean to indicate success, like the other existing "compare and
   swap" wrappers

 - Add documentation for HWCAP flags

 - Switch to obtaining total RAM pages from memblock instead of
   totalram_pages() during mm init, to ensure correct calculation of
   zero page size, when defer_init is enabled

 - Refactor lowcore access and switch to using the get_lowcore()
   function instead of the S390_lowcore macro

 - Cleanups for PG_arch_1 and folio handling in UV and hugetlb code

 - Add missing MODULE_DESCRIPTION() macros

 - Fix VM_FAULT_HWPOISON handling in do_exception()

* tag 's390-6.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (54 commits)
  s390/mm: Fix VM_FAULT_HWPOISON handling in do_exception()
  s390/kvm: Move bitfields for dat tables
  s390/entry: Pass the asce as parameter to sie64a()
  s390/sthyi: Use cached data when diag is busy
  s390/sthyi: Move diag operations
  s390/hypfs_diag: Diag204 busy loop
  s390/diag: Add busy-indication-facility requirements
  s390/diag: Diag204 add busy return errno
  s390/diag: Return errno's from diag204
  s390/sclp: Diag204 busy indication facility detection
  s390/atomic_ops: Make use of flag output constraint
  s390/atomic_ops: Improve __atomic_set() for small values
  s390/atomic_ops: Use symbolic names
  s390/smp: Switch to GENERIC_CPU_DEVICES
  s390/hwcaps: Add documentation for HWCAP flags
  s390/pgtable: Make crdte() and cspg() return a value
  s390/topology: Remove CPU KOBJ_CHANGE uevents
  s390/sclp: Add timeout to Store Data requests
  s390/sclp: Prevent release of buffer in I/O
  s390/sclp: Suppress unnecessary Store Data warning
  ...

Merge tag 'kvm-x86-generic-6.11' of https://github.com/kvm-x86/linux into HEAD

2024-07-16T13:51:36+00:00

KVM generic changes for 6.11

 - 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.

 - A few minor cleanups

Merge tag 'loongarch-kvm-6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson into HEAD

2024-07-12T15:24:12+00:00

LoongArch KVM changes for v6.11

1. Add ParaVirt steal time support.
2. Add some VM migration enhancement.
3. Add perf kvm-stat support for loongarch.

s390/kvm: Move bitfields for dat tables

2024-07-10T17:50:45+00:00

Move and improve the struct definitions for DAT tables from gaccess.c
to a new header.

Once in a separate header, the structs become available everywhere. One
possible usecase is to merge them in the s390 pte_t and p?d_t
definitions, which is left as an exercise for the reader.

Signed-off-by: Claudio Imbrenda 
Reviewed-by: Nico Boehr 
Link: https://lore.kernel.org/r/20240703155900.103783-3-imbrenda@linux.ibm.com
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/entry: Pass the asce as parameter to sie64a()

2024-07-10T17:50:45+00:00

Pass the guest ASCE explicitly as parameter, instead of having sie64a()
take it from lowcore.

This removes hidden state from lowcore, and makes things look cleaner.

Signed-off-by: Claudio Imbrenda 
Reviewed-by: Nico Boehr 
Link: https://lore.kernel.org/r/20240703155900.103783-2-imbrenda@linux.ibm.com
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik