Currently we have a couple of helpers to manipulate bits in particular
sysregs:
* config_sctlr_el1(u32 clear, u32 set)
* change_cpacr(u64 val, u64 mask)
The parameters of these differ in naming convention, order, and size,
which is unfortunate. They also differ slightly in behaviour, as
change_cpacr() skips the sysreg write if the bits are unchanged, which
is a useful optimization when sysreg writes are expensive.
Before we gain yet another sysreg manipulation function, let's
unify these with a common helper, providing a consistent order for
clear/set operands, and the write skipping behaviour from
change_cpacr(). Code will be migrated to the new helper in subsequent
patches.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
When booting a 64 KB pages kernel on a ACPI GICv3 system that
implements support for v2 emulation, the following warning is
produced
GICV size 0x2000 not a multiple of page size 0x10000
and support for v2 emulation is disabled, preventing GICv2 VMs
from being able to run on such hosts.
The reason is that vgic_v3_probe() performs a sanity check on the
size of the window (it should be a multiple of the page size),
while the ACPI MADT parsing code hardcodes the size of the window
to 8 KB. This makes sense, considering that ACPI does not bother
to describe the size in the first place, under the assumption that
platforms implementing ACPI will follow the architecture and not
put anything else in the same 64 KB window.
So let's just drop the sanity check altogether, and assume that
the window is at least 64 KB in size.
Fixes: 9097773245 ("KVM: arm/arm64: vgic-new: vgic_init: implement kvm_vgic_hyp_init")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
The audio divider is one based. This offset was mistakenly dropped from
recalc_rate() when migrating to clk_regmap.
Fixes: 88a4e12836 ("clk: meson: migrate the audio divider clock to clk_regmap")
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Rather than leaving io queues quiesced after tearing down an association,
restart them. This allows ios to be replayed, with fastfail ios terminating
and non-fastfail getting into loops of retry.
This follows rdma's lead.
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Sagi Grimberg <sagi@grimber.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The pr_warn in l1tf_select_mitigation would have used the prior pr_fmt
which was defined as "Spectre V2 : ".
Move the function to be past SSBD and also define the pr_fmt.
Fixes: 17dbca1193 ("x86/speculation/l1tf: Add sysfs reporting for l1tf")
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
sha: 702353b538 ("selftest: add test for TCP_INQ") forgot to add
tcp_inq to .gitignore.
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
When delta passed to gem_ptp_adjtime is negative, the sign is
maintained in the ns_to_timespec64 conversion. Hence timespec_add
should be used directly. timespec_sub will just subtract the negative
value thus increasing the time difference.
Signed-off-by: Harini Katakam <harini.katakam@xilinx.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 296d485680 ("ipvlan: inherit MTU from master device") adjusted
the mtu from the master device when creating a ipvlan device, but it
would also override the mtu value set in rtnl_create_link. It causes
IFLA_MTU param not to take effect.
So this patch is to not adjust the mtu if IFLA_MTU param is set when
creating a ipvlan device.
Fixes: 296d485680 ("ipvlan: inherit MTU from master device")
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently it is incrementing SctpFragUsrMsgs when the user message size
is of the exactly same size as the maximum fragment size, which is wrong.
The fix is to increment it only when user message is bigger than the
maximum fragment size.
Fixes: bfd2e4b873 ("sctp: refactor sctp_datamsg_from_user")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After commit 9facc33687 ("bpf: reject any prog that failed read-only lock")
offsetof(struct bpf_binary_header, image) became 3 instead of 4,
breaking powerpc BPF badly, since instructions need to be word aligned.
Fixes: 9facc33687 ("bpf: reject any prog that failed read-only lock")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
When injecting frames in the Ocelot switch driver an injection header
(IFH) should be used to configure various parameters related to a given
frame, such as the port onto which the frame should be departed or its
vlan id. Other parameters in the switch configuration can led to an
injected frame being sent without an IFH but this led to various issues
as the per-frame parameters are then not used. This is especially true
when using multiple ports for injection.
The IFH was injected with the wrong endianness which led to the switch
not taking it into account as the IFH_INJ_BYPASS bit was then unset.
(The bit tells the switch to use the IFH over its internal
configuration). This patch fixes it.
In addition to the endianness fix, the IFH is also fixed. As it was
(unwillingly) unused, some of its fields were not configured the right
way.
Fixes: a556c76adc ("net: mscc: Add initial Ocelot switch support")
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Device tree based systems without of_dev_auxdata will have the mdio
device named differently than "davinci_mdio(.0)". In this case use the
device's parent's compatible string for matching
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If NBD_DISCONNECT_ON_CLOSE is set on a device, then the driver will
issue a disconnect from nbd_release if the device has no remaining
bdev->bd_openers.
Fix ret val so reconfigure with only setting the flag succeeds.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Doron Roberts-Kedes <doronrk@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pass the correct thing to rtl8169_interrupt() from netpoll.
Cc: Realtek linux nic maintainers <nic_swsd@realtek.com>
Cc: netdev@vger.kernel.org
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Fixes: ebcd5daa7f ("r8169: change interrupt handler argument type")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In function strp_data_ready(), it is useless to call queue_work if
the state of strparser is already paused. The state checking should
be done before calling queue_work. The change reduces the context
switches and improves the ktls-rx throughput by approx 20% (measured
on cortex-a53 based platform).
Signed-off-by: Vakul Garg <vakul.garg@nxp.com>
Acked-by: Dave Watson <davejwatson@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add fragments to pass bridge and vlan tests.
Fixes: 33b01b7b4f ("selftests: add rtnetlink test script")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use $(OBJDUMP) instead of literal 'objdump' to avoid
using host toolchain when cross compiling.
Fixes: 421780fd49 ("bpfilter: fix build error")
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Reported-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
machine_desc->init_per_cpu() hook is supposed to be per cpu
initialization and would seem to apply equally to UP and/or SMP.
Infact the comment in header file seems to suggest it works for
UP too, which was not the case and this patch.
This enables !CONFIG_SMP build for platforms such as hsdk.
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[vgupta: trimmeed changelog]
Pull turbostat utility changes for 4.18-rc2 from Len Brown.
"This includes two regression fixes, plus a couple more random, but
worthy, patches."
* 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
tools/power turbostat: version 18.06.20
tools/power turbostat: add the missing command line switches
tools/power turbostat: add single character tokens to help
tools/power turbostat: alphabetize the help output
tools/power turbostat: fix segfault on 'no node' machines
tools/power turbostat: add optional APIC X2APIC columns
tools/power turbostat: decode cpuid.1.HT
tools/power turbostat: fix show/hide issues resulting from mis-merge
Regression and crashing bug fixes:
- mlx4/5: Fixes for issues found from various checkers
- A resource tracking and uverbs regression in the core code
- qedr: NULL pointer regression found during testing
- rxe: Various small bugs
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
Pull rdma fixes from Jason Gunthorpe:
"Here are eight fairly small fixes collected over the last two weeks.
Regression and crashing bug fixes:
- mlx4/5: Fixes for issues found from various checkers
- A resource tracking and uverbs regression in the core code
- qedr: NULL pointer regression found during testing
- rxe: Various small bugs"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
IB/rxe: Fix missing completion for mem_reg work requests
RDMA/core: Save kernel caller name when creating CQ using ib_create_cq()
IB/uverbs: Fix ordering of ucontext check in ib_uverbs_write
IB/mlx4: Fix an error handling path in 'mlx4_ib_rereg_user_mr()'
RDMA/qedr: Fix NULL pointer dereference when running over iWARP without RDMA-CM
IB/mlx5: Fix return value check in flow_counters_set_data()
IB/mlx5: Fix memory leak in mlx5_ib_create_flow
IB/rxe: avoid double kfree skb
Pull networking fixes from David Miller:
1) Fix crash on bpf_prog_load() errors, from Daniel Borkmann.
2) Fix ATM VCC memory accounting, from David Woodhouse.
3) fib6_info objects need RCU freeing, from Eric Dumazet.
4) Fix SO_BINDTODEVICE handling for TCP sockets, from David Ahern.
5) Fix clobbered error code in enic_open() failure path, from
Govindarajulu Varadarajan.
6) Propagate dev_get_valid_name() error returns properly, from Li
RongQing.
7) Fix suspend/resume in davinci_emac driver, from Bartosz Golaszewski.
8) Various act_ife fixes (recursive locking, IDR leaks, etc.) from
Davide Caratti.
9) Fix buggy checksum handling in sungem driver, from Eric Dumazet.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (40 commits)
ip: limit use of gso_size to udp
stmmac: fix DMA channel hang in half-duplex mode
net: stmmac: socfpga: add additional ocp reset line for Stratix10
net: sungem: fix rx checksum support
bpfilter: ignore binary files
bpfilter: fix build error
net/usb/drivers: Remove useless hrtimer_active check
net/sched: act_ife: preserve the action control in case of error
net/sched: act_ife: fix recursive lock and idr leak
net: ethernet: fix suspend/resume in davinci_emac
net: propagate dev_get_valid_name return code
enic: do not overwrite error code
net/tcp: Fix socket lookups with SO_BINDTODEVICE
ptp: replace getnstimeofday64() with ktime_get_real_ts64()
net/ipv6: respect rcu grace period before freeing fib6_info
net: net_failover: fix typo in net_failover_slave_register()
ipvlan: use ETH_MAX_MTU as max mtu
net: hamradio: use eth_broadcast_addr
enic: initialize enic->rfs_h.lock in enic_probe
MAINTAINERS: Add Sam as the maintainer for NCSI
...
Starting Icelake silicon supports 10-bpc hdmi to support certain
media workloads. Currently hdmi supports 8 and 12 bpc. Plumbed
in support for 10 bit hdmi.
Cc: James Ausmus <james.ausmus@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180522002558.29262-18-paulo.r.zanoni@intel.com
Now the PXA is converted to new ac97 bus support, the wm9713 is
automatically detected and probed. Remove it from the platform bus.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
The AC97 bit clock is added as the pxa internally generated 13MHz
clock. This is a consequence of the new ac97 framework.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
The usb client of the hx4700 is not working because no platform data is
declared. Fix it by adding the missing call.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Currently for the psr_table->tp2_tp3_wakeup_time case 3 there appears
to be a copy-paste error from the previous switch statement where
dev_priv->vbt.psr.tp1_wakeup_time_us is being assigned and I believe
it should be dev_priv->vbt.psr.tp2_tp3_wakeup_time_us that should be
assigned instead.
Detected by CoverityScan, CID#1470105 ("Copy-paste error")
Fixes: 77312ae8f0 ("drm/i915/psr: vbt change for psr")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180620132543.28092-1-colin.king@canonical.com
resp->num is the number of tokens in resp->tok[]. It gets set in
response_parse(). So if n == resp->num then we're reading beyond the
end of the data.
Fixes: 455a7b238c ("block: Add Sed-opal library")
Reviewed-by: Scott Bauer <scott.bauer@intel.com>
Tested-by: Scott Bauer <scott.bauer@intel.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Document the missing command line tokens in the help() function.
Signed-off-by: Nathan Ciobanu <nathan.d.ciobanu@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Improve the help() output by adding the single character
tokens (e.g -a).
Signed-off-by: Nathan Ciobanu <nathan.d.ciobanu@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Sort the command line arguments output of help() in
alphabetical order in line with other linux tools.
Signed-off-by: Nathan Ciobanu <nathan.d.ciobanu@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Running turbostat on machines that don't expose nodes
in sysfs (no /sys/bus/node) causes a segfault or a -nan
value diesplayed in the log. This is caused by
physical_node_id being reported as -1 and logical_node_id
being calculated as a negative number resulting in the new
GET_THREAD/GET_CORE returning an incorrect address.
Signed-off-by: Nathan Ciobanu <nathan.d.ciobanu@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Add APIC and X2APIC columns to the topology section.
They are disabled-by-default -- enable like so:
--debug
or
--enable APIC,X2APIC
Signed-off-by: Len Brown <len.brown@intel.com>
The --show and --hide options failed on "Node", which was listed as "Node%".
The --show and --hide options were generally fouled-up do due to come
content merges that scrambled the list of column name indexes.
Signed-off-by: Len Brown <len.brown@intel.com>
commit 5422b37c90 ("drm/i915/psr: Kill delays when activating psr
back.") removed the call to cancel a scheduled psr_work from
psr_disable() and instead added an early return in the work function. But,
if the scheduled work item is executed after psr_enable(), we end up
printing warnings as PSR is already enabled and active. So, put the
cancel_work call back in psr_disable().
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Fixes: 5422b37c90 ("drm/i915/psr: Kill delays when activating psr back.")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106948
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180618220207.2778-1-dhinakaran.pandiyan@intel.com
If rq_state == ARRAY_SIZE() then we read one element beyond the end of
the blk_mq_rq_state_name_array[] array.
Fixes: ec6dcf63c5 ("blk-mq-debugfs: Show more request state information")
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For the L1TF workaround its necessary to limit the swap file size to below
MAX_PA/2, so that the higher bits of the swap offset inverted never point
to valid memory.
Add a mechanism for the architecture to override the swap file size check
in swapfile.c and add a x86 specific max swapfile check function that
enforces that limit.
The check is only enabled if the CPU is vulnerable to L1TF.
In VMs with 42bit MAX_PA the typical limit is 2TB now, on a native system
with 46bit PA it is 32TB. The limit is only per individual swap file, so
it's always possible to exceed these limits with multiple swap files or
partitions.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
For L1TF PROT_NONE mappings are protected by inverting the PFN in the page
table entry. This sets the high bits in the CPU's address space, thus
making sure to point to not point an unmapped entry to valid cached memory.
Some server system BIOSes put the MMIO mappings high up in the physical
address space. If such an high mapping was mapped to unprivileged users
they could attack low memory by setting such a mapping to PROT_NONE. This
could happen through a special device driver which is not access
protected. Normal /dev/mem is of course access protected.
To avoid this forbid PROT_NONE mappings or mprotect for high MMIO mappings.
Valid page mappings are allowed because the system is then unsafe anyways.
It's not expected that users commonly use PROT_NONE on MMIO. But to
minimize any impact this is only enforced if the mapping actually refers to
a high MMIO address (defined as the MAX_PA-1 bit being set), and also skip
the check for root.
For mmaps this is straight forward and can be handled in vm_insert_pfn and
in remap_pfn_range().
For mprotect it's a bit trickier. At the point where the actual PTEs are
accessed a lot of state has been changed and it would be difficult to undo
on an error. Since this is a uncommon case use a separate early page talk
walk pass for MMIO PROT_NONE mappings that checks for this condition
early. For non MMIO and non PROT_NONE there are no changes.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
L1TF core kernel workarounds are cheap and normally always enabled, However
they still should be reported in sysfs if the system is vulnerable or
mitigated. Add the necessary CPU feature/bug bits.
- Extend the existing checks for Meltdowns to determine if the system is
vulnerable. All CPUs which are not vulnerable to Meltdown are also not
vulnerable to L1TF
- Check for 32bit non PAE and emit a warning as there is no practical way
for mitigation due to the limited physical address bits
- If the system has more than MAX_PA/2 physical memory the invert page
workarounds don't protect the system against the L1TF attack anymore,
because an inverted physical address will also point to valid
memory. Print a warning in this case and report that the system is
vulnerable.
Add a function which returns the PFN limit for the L1TF mitigation, which
will be used in follow up patches for sanity and range checks.
[ tglx: Renamed the CPU feature bit to L1TF_PTEINV ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
The L1TF workaround doesn't make any attempt to mitigate speculate accesses
to the first physical page for zeroed PTEs. Normally it only contains some
data from the early real mode BIOS.
It's not entirely clear that the first page is reserved in all
configurations, so add an extra reservation call to make sure it is really
reserved. In most configurations (e.g. with the standard reservations)
it's likely a nop.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
When PTEs are set to PROT_NONE the kernel just clears the Present bit and
preserves the PFN, which creates attack surface for L1TF speculation
speculation attacks.
This is important inside guests, because L1TF speculation bypasses physical
page remapping. While the host has its own migitations preventing leaking
data from other VMs into the guest, this would still risk leaking the wrong
page inside the current guest.
This uses the same technique as Linus' swap entry patch: while an entry is
is in PROTNONE state invert the complete PFN part part of it. This ensures
that the the highest bit will point to non existing memory.
The invert is done by pte/pmd_modify and pfn/pmd/pud_pte for PROTNONE and
pte/pmd/pud_pfn undo it.
This assume that no code path touches the PFN part of a PTE directly
without using these primitives.
This doesn't handle the case that MMIO is on the top of the CPU physical
memory. If such an MMIO region was exposed by an unpriviledged driver for
mmap it would be possible to attack some real memory. However this
situation is all rather unlikely.
For 32bit non PAE the inversion is not done because there are really not
enough bits to protect anything.
Q: Why does the guest need to be protected when the HyperVisor already has
L1TF mitigations?
A: Here's an example:
Physical pages 1 2 get mapped into a guest as
GPA 1 -> PA 2
GPA 2 -> PA 1
through EPT.
The L1TF speculation ignores the EPT remapping.
Now the guest kernel maps GPA 1 to process A and GPA 2 to process B, and
they belong to different users and should be isolated.
A sets the GPA 1 PA 2 PTE to PROT_NONE to bypass the EPT remapping and
gets read access to the underlying physical page. Which in this case
points to PA 2, so it can read process B's data, if it happened to be in
L1, so isolation inside the guest is broken.
There's nothing the hypervisor can do about this. This mitigation has to
be done in the guest itself.
[ tglx: Massaged changelog ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Dave Hansen <dave.hansen@intel.com>
With L1 terminal fault the CPU speculates into unmapped PTEs, and resulting
side effects allow to read the memory the PTE is pointing too, if its
values are still in the L1 cache.
For swapped out pages Linux uses unmapped PTEs and stores a swap entry into
them.
To protect against L1TF it must be ensured that the swap entry is not
pointing to valid memory, which requires setting higher bits (between bit
36 and bit 45) that are inside the CPUs physical address space, but outside
any real memory.
To do this invert the offset to make sure the higher bits are always set,
as long as the swap file is not too big.
Note there is no workaround for 32bit !PAE, or on systems which have more
than MAX_PA/2 worth of memory. The later case is very unlikely to happen on
real systems.
[AK: updated description and minor tweaks by. Split out from the original
patch ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Dave Hansen <dave.hansen@intel.com>
If pages are swapped out, the swap entry is stored in the corresponding
PTE, which has the Present bit cleared. CPUs vulnerable to L1TF speculate
on PTE entries which have the present bit set and would treat the swap
entry as phsyical address (PFN). To mitigate that the upper bits of the PTE
must be set so the PTE points to non existent memory.
The swap entry stores the type and the offset of a swapped out page in the
PTE. type is stored in bit 9-13 and offset in bit 14-63. The hardware
ignores the bits beyond the phsyical address space limit, so to make the
mitigation effective its required to start 'offset' at the lowest possible
bit so that even large swap offsets do not reach into the physical address
space limit bits.
Move offset to bit 9-58 and type to bit 59-63 which are the bits that
hardware generally doesn't care about.
That, in turn, means that if you on desktop chip with only 40 bits of
physical addressing, now that the offset starts at bit 9, there needs to be
30 bits of offset actually *in use* until bit 39 ends up being set, which
means when inverted it will again point into existing memory.
So that's 4 terabyte of swap space (because the offset is counted in pages,
so 30 bits of offset is 42 bits of actual coverage). With bigger physical
addressing, that obviously grows further, until the limit of the offset is
hit (at 50 bits of offset - 62 bits of actual swap file coverage).
This is a preparatory change for the actual swap entry inversion to protect
against L1TF.
[ AK: Updated description and minor tweaks. Split into two parts ]
[ tglx: Massaged changelog ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Dave Hansen <dave.hansen@intel.com>
L1 Terminal Fault (L1TF) is a speculation related vulnerability. The CPU
speculates on PTE entries which do not have the PRESENT bit set, if the
content of the resulting physical address is available in the L1D cache.
The OS side mitigation makes sure that a !PRESENT PTE entry points to a
physical address outside the actually existing and cachable memory
space. This is achieved by inverting the upper bits of the PTE. Due to the
address space limitations this only works for 64bit and 32bit PAE kernels,
but not for 32bit non PAE.
This mitigation applies to both host and guest kernels, but in case of a
64bit host (hypervisor) and a 32bit PAE guest, inverting the upper bits of
the PAE address space (44bit) is not enough if the host has more than 43
bits of populated memory address space, because the speculation treats the
PTE content as a physical host address bypassing EPT.
The host (hypervisor) protects itself against the guest by flushing L1D as
needed, but pages inside the guest are not protected against attacks from
other processes inside the same guest.
For the guest the inverted PTE mask has to match the host to provide the
full protection for all pages the host could possibly map into the
guest. The hosts populated address space is not known to the guest, so the
mask must cover the possible maximal host address space, i.e. 52 bit.
On 32bit PAE the maximum PTE mask is currently set to 44 bit because that
is the limit imposed by 32bit unsigned long PFNs in the VMs. This limits
the mask to be below what the host could possible use for physical pages.
The L1TF PROT_NONE protection code uses the PTE masks to determine which
bits to invert to make sure the higher bits are set for unmapped entries to
prevent L1TF speculation attacks against EPT inside guests.
In order to invert all bits that could be used by the host, increase
__PHYSICAL_PAGE_SHIFT to 52 to match 64bit.
The real limit for a 32bit PAE kernel is still 44 bits because all Linux
PTEs are created from unsigned long PFNs, so they cannot be higher than 44
bits on a 32bit kernel. So these extra PFN bits should be never set. The
only users of this macro are using it to look at PTEs, so it's safe.
[ tglx: Massaged changelog ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
