Intercept and report #UD to VM on SVM/AMD in case VM tried to execute an
SVM instruction. Otherwise, SVM allows execution of them, and instructions
operate on host physical addresses despite being executed in guest mode.
Reported by: Maxime Villard <max@m00nbsd.net>
admbug: 972
CVE: CVE-2020-7467
Reviewed by: grehan, markj
Differential revision: https://reviews.freebsd.org/D26313
The flag requests entry of non-managed superpage mapping of size
pagesizes[psind] into the page table.
Pmap supports fake wiring of the largepage mappings. Only attributes
of the largepage mapping can be changed by calling pmap_enter(9) over
existing mapping, physical address of the page must be unchanged.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D24652
Currently we use a single bit to indicate whether the virtual page is
part of a superpage. To support a forthcoming implementation of
non-transparent 1GB superpages, it is useful to provide more detailed
information about large page sizes.
The change converts MINCORE_SUPER into a mask for MINCORE_PSIND(psind)
values, indicating a mapping of size psind, where psind is an index into
the pagesizes array returned by getpagesizes(3), which in turn comes
from the hw.pagesizes sysctl. MINCORE_PSIND(1) is equal to the old
value of MINCORE_SUPER.
For now, two bits are used to record the page size, permitting values
of MAXPAGESIZES up to 4.
Reviewed by: alc, kib
Sponsored by: Juniper Networks, Inc.
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D26238
This allows privileged userspace processes to find information about the
physical page backing a given mapping. It is useful in applications
such as DPDK which perform some of their own memory management.
Reviewed by: kib, jhb (previous version)
MFC after: 2 weeks
Sponsored by: Juniper Networks, Inc.
Sponsored by: Klara Inc.
Differential Revision: https://reviews.freebsd.org/D26237
If the call to _pmap_allocpte() is not sleepable, it is possible that
allocation of PML4 or PDP page is successful but either PDP or PD page
is not. Restructured code in _pmap_allocpte() leaves zero-referenced
page in the paging structure.
Handle it by checking refcount of the page one level above failed
alloc and free that page if its reference count is zero.
Reported and tested by: pho
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26293
We can switch into long mode directly with LA57 enabled.
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D25273
Since LA57 was moved to the main SDM document with revision 072, it
seems that we should have a support for it, and silicons are coming.
This patch makes pmap support both LA48 and LA57 hardware. The
selection of page table level is done at startup, kernel always
receives control from loader with 4-level paging. It is not clear how
UEFI spec would adapt LA57, for instance it could hand out control in
LA57 mode sometimes.
To switch from LA48 to LA57 requires turning off long mode, requesting
LA57 in CR4, then re-entering long mode. This is somewhat delicate
and done in pmap_bootstrap_la57(). AP startup in LA57 mode is much
easier, we only need to toggle a bit in CR4 and load right value in CR3.
I decided to not change kernel map for now. Single PML5 entry is
created that points to the existing kernel_pml4 (KML4Phys) page, and a
pml5 entry to create our recursive mapping for vtopte()/vtopde().
This decision is motivated by the fact that we cannot overcommit for
KVA, so large space there is unusable until machines start providing
wider physical memory addressing. Another reason is that I do not
want to break our fragile autotuning, so the KVA expansion is not
included into this first step. Nice side effect is that minidumps are
compatible.
On the other hand, (very) large address space is definitely
immediately useful for some userspace applications.
For userspace, numbering of pte entries (or page table pages) is
always done for 5-level structures even if we operate in 4-level mode.
The pmap_is_la57() function is added to report the mode of the
specified pmap, this is done not to allow simultaneous 4-/5-levels
(which is not allowed by hw), but to accomodate for EPT which has
separate level control and in principle might not allow 5-leve EPT
despite x86 paging supports it. Anyway, it does not seems critical to
have 5-level EPT support now.
Tested by: pho (LA48 hardware)
Reviewed by: alc
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D25273
Coverity has identified the line in this change as "Potential integer
overflowing expression" due to the variable i declared as an int
and used in an expression with vm_paddr_t, a 64bit variable.
This change has very little effect as when this line is execute
nkpt is small and phys_addr is a the beginning of physical memory.
But there is no explicit protection that the above is true.
Submitted by: bret_ketchum@dell.com
Reported by: Coverity
Reviewed by: markj
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D26141
The ACPI table-mapping code used pmap_kenter_temporary() to create
mappings, which in turn uses the fixed-size crashdump map. Moreover,
the code was not verifying that the table fits in this map, so when
mapping large tables we could clobber adjacent mappings. This use of
pmap_kenter_temporary() appears to predate support in pmap_mapbios() for
creating early mappings, but that restriction no longer applies.
PR: 248746
Reviewed by: kib, mav
Tested by: gallatin, Curtis Villamizar <curtis@ipv6.occnc.com>
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D26125
Those messages were printed hundreds of times during boot, often multiple
times for each table. We already print information about the tables in
more organized form once to not duplicate it when random ACPI drivers are
attaching.
MFC after: 1 week
This is a step towards facilitating jails with only Linux binaries.
Supporting emul_path adds path lookups which are completely spurious
if the binary at hand runs in a Linux-based root directory.
It defaults to on (== current behavior).
make -C /root/linux-5.3-rc8 -s -j 1 bzImage:
use_emul_path=1: 101.65s user 68.68s system 100% cpu 2:49.62 total
use_emul_path=0: 101.41s user 64.32s system 100% cpu 2:45.02 total
Recent versions of UEFI have moved local APIC timer initialization into
the early SEC phase which runs out of ROM, prior to self-relocating
into RAM. This results in a hypervisor exit.
Currently bhyve prevents instruction emulation from segments that aren't
marked as "sysmem" aka guest RAM, with the vm_gpa_hold() routine failing.
However, there is no reason for this restriction: the hypervisor already
controls whether EPT mappings are marked as executable.
Fix by dropping the redundant check of sysmem.
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D25955
so we don't ifdef for every arch in busdma_iommu.c;
o No need to include specialreg.h for x86, remove it.
Requested by: andrew
Reviewed by: kib
Sponsored by: DARPA/AFRL
Differential Revision: https://reviews.freebsd.org/D25957
For purposes of handling hardware error reported via NMIs I need a way to
escape NMI context, being too restrictive to do something significant.
To do it this change introduces new swi_sched() flag SWI_FROMNMI, making
it careful about used KPIs. On platforms allowing IPI sending from NMI
context (x86 for now) it immediately wakes clk_intr_event via new IPI_SWI,
otherwise it works just like SWI_DELAY. To handle the delayed SWIs this
patch calls clk_intr_event on every hardclock() tick.
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D25754
Being able to use tmpfs without kernel modules is very useful when building
small MFS_ROOT kernels without a real file system.
Including TMPFS also matches arm/GENERIC and the MIPS std.MALTA configs.
Compiling TMPFS only adds 4 .c files so this should not make much of a
difference to NO_MODULES build times (as we do for our minimal RISC-V
images).
Reviewed By: br (earlier version for riscv), brooks, emaste
Differential Revision: https://reviews.freebsd.org/D25317
The only part of nmi_handle_intr() depending on ISA is isa_nmi(), which is
already wrapped. Entering debugger on NMI does not really depend on ISA.
MFC after: 2 weeks
Limit manipulations to use %rax as scratch to the pti portion of the
syscall entry code.
Submitted by: alc
Reviewed by: markj
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D25722
When pmap operates in PTI mode, we must reload %cr3 on return to
userspace. In non-PCID mode the reload always flushes all non-global
TLB entries and we take advantage of it by only invalidating the KPT
TLB entries (there is no cached UPT entries at all).
In PCID mode, we flush both KPT and UPT TLB explicitly, but we can
take advantage of the fact that PCID mode command to reload %cr3
includes a flag to flush/not flush target TLB. In particular, we can
avoid the flush for UPT, instead record that load of pc_ucr3 into %cr3
on return to usermode should be flushing. This is done by providing
either all-1s or ~CR3_PCID_MASK in pc_ucr3_load_mask. The mask is
automatically reset to all-1s on return to usermode.
Similarly, we can avoid flushing UPT TLB on context switch, replacing
it by setting pc_ucr3_load_mask. This unifies INVPCID and non-INVPCID
PTI ifunc, leaving only 4 cases instead of 6. This trick is also
applicable both to the TLB shootdown IPI handlers, since handlers
interrupt the target thread.
But then we need to check pc_curpmap in handlers, and this would
reopen the same race for INVPCID machines as was fixed in r306350 for
non-INVPCID. To not introduce the same bug, unconditionally do
spinlock_enter() in pmap_activate().
Reviewed by: alc, markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
Differential revision: https://reviews.freebsd.org/D25483
Subsequent to r240317, kmem_free() was replaced with kva_free() (r254025).
kva_free() releases the KVA allocation for the mapped region, but no longer
clears the pmap (pagetable) entries.
An affected pmap_unmapdev operation would leave the still-pmap'd VA space
free for allocation by other KVA consumers. However, this bug easily
avoided notice for ~7 years because most devices (1) never call
pmap_unmapdev and (2) on amd64, mostly fit within the DMAP and do not need
KVA allocations. Other affected arch are less popular: i386, MIPS, and
PowerPC. Arm64, arm32, and riscv are not affected.
Reported by: Don Morris <dgmorris AT earthlink.net>
Submitted by: Don Morris (amd64 part)
Reviewed by: kib, markj, Don (!amd64 parts)
MFC after: I don't intend to, but you might want to
Sponsored by: Dell Isilon
Differential Revision: https://reviews.freebsd.org/D25689
This removes SCTP from in-tree kernel configuration files. Now, SCTP
can be enabled by simply loading the module, as discussed on
freebsd-net@.
Reviewed by: tuexen
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D25611
This shortens fdalloc by over 60 bytes. Correctness verified by running both
variants at the same time and comparing the result of each call.
Note someone(tm) should make a pass at converting everything else feasible.
Stop using smp_ipi_mtx to protect global shootdown state, and
move/multiply the global state into pcpu. Now each CPU can initiate
shootdown IPI independently from other CPUs. Initiator enters
critical section, then fills its local PCPU shootdown info
(pc_smp_tlb_XXX), then clears scoreboard generation at location (cpu,
my_cpuid) for each target cpu. After that IPI is sent to all targets
which scan for zeroed scoreboard generation words. Upon finding such
word the shootdown data is read from corresponding cpu' pcpu, and
generation is set. Meantime initiator loops waiting for all zeroed
generations in scoreboard to update.
Initiator does not disable interrupts, which should allow
non-invalidation IPIs from deadlocking, it only needs to disable
preemption to pin itself to the instance of the pcpu smp_tlb data.
The generation is set before the actual invalidation is performed in
handler. It is safe because target CPU cannot return to userspace
before handler finishes. In principle only NMI can preempt the
handler, but NMI would see the kernel handler frame and not touch
not-invalidated user page table.
Handlers loop until they do not see zeroed scoreboard generations.
This, together with hardware keeping one pending IPI in LAPIC IRR
should prevent lost shootdowns.
Notes.
1. The code does protect writes to LAPIC ICR with exclusion. I believe
this is fine because we in fact do not send IPIs from interrupt
handlers. More for !x2APIC mode where ICR access for write requires
two registers write, we disable interrupts around it. If considered
incorrect, I can add per-cpu spinlock around ipi_send().
2. Scoreboard lines owned by given target CPU can be padded to the
cache line, to reduce ping-pong.
Reviewed by: markj (previous version)
Discussed with: alc
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
Differential revision: https://reviews.freebsd.org/D25510
On architectures that use RELA relocations it is safe to rerun the ifunc
resolvers on after all CPUs have started, but while they are sill parked.
On arm64 with big.LITTLE this is needed as some SoCs have shipped with
different ID register values the big and little clusters meaning we were
unable to rely on the register values from the boot CPU.
Add support for rerunning the resolvers on arm64 and amd64 as these are
both RELA using architectures.
Reviewed by: kib
Sponsored by: Innovate UK
Differential Revision: https://reviews.freebsd.org/D25455
Like other types of allocation, fpu_kern_ctx are frequently allocated per-cpu.
Provide the API and sketch some example consumers.
fpu_kern_alloc_ctx_domain() preferentially allocates memory from the
provided domain, and falls back to other domains if that one is empty
(DOMAINSET_PREF(domain) policy).
Maybe it makes more sense to just shove one of these in the DPCPU area
sooner or later -- left for future work.
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D22053
Take advantage of Warner's nice new real GEOM aliasing system and use it for
aliased partition names that actually work.
Our canonical EBR partition name is the weird, not-default-on-x86-prior-to-
this-revision "da1p4+00001234." However, if compatibility mode (tunable
kern.geom.part.ebr.compat_aliases) is enabled (1, default), we continue to
provide the alias names like "da1p5" in addition to the weird canonical
names.
Naming partition providers was just one aspect of the COMPAT knob; in
addition it limited mutability, in part because it did not preserve existing
EBR header content aside from that of LBA 0. This change saves the EBR
header for LBA 0, as well as for every EBR partition encountered. That way,
when we write out the EBR partition table on modification, we can restore
any bootloader or other metadata in both LBA0 (the first data-containing EBR
may start after 0) as well as every logical EBR we read from the disk, and
only update the geometry metadata and linked list pointers that describe the
actual partitioning.
(This change does not add support for the 'bootcode' verb to EBR.)
PR: 232463
Reported by: Manish Jain <bourne.identity AT hotmail.com>
Discussed with: ae (no objection)
Relnotes: maybe
Differential Revision: https://reviews.freebsd.org/D24939
This effectively mirrors our libc implementation, but with minor fudging --
name needs to be copied in from userspace, so we just copy it straight into
stack-allocated memfd_name into the correct position rather than allocating
memory that needs to be cleaned up.
The sealing-related fcntl(2) commands, F_GET_SEALS and F_ADD_SEALS, have
also been implemented now that we support them.
Note that this implementation is still not quite at feature parity w.r.t.
the actual Linux version; some caveats, from my foggy memory:
- Need to implement SHM_GROW_ON_WRITE, default for memfd (in progress)
- LTP wants the memfd name exposed to fdescfs
- Linux allows open() of an fdescfs fd with O_TRUNC to truncate after dup.
(?)
Interested parties can install and run LTP from ports (devel/linux-ltp) to
confirm any fixes.
PR: 240874
Reviewed by: kib, trasz
Differential Revision: https://reviews.freebsd.org/D21845
