According to ipmi spec, block number is a number that is incremented,
starting with 0, for each new block of message data returned using the
middle transaction.

Here, the 'blocknum' is data[0] which always starts from zero(0) and
'ssif_info->multi_pos' starts from 1.
So, we need to add +1 to blocknum while comparing with multi_pos.

Fixes: 7d6380cd ("ipmi:ssif: Fix handling of multi-part return messages").
Reported-by: Kiran Kolukuluru <kirank@ami.com>
Signed-off-by: Kamlakant Patel <kamlakantp@marvell.com>
Message-Id: <1556106615-18722-1-git-send-email-kamlakantp@marvell.com>
[Also added a debug log if the block numbers don't match.]
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: stable@vger.kernel.org # 4.4

This is required for SSIF to work.

There was no way to know if the interface being added was SI
or SSIF from the platform data, but that was required so the
i2c-addr is only added for SSIF interfaces.  So add a field
for that.

Also rework the logic a bit so that ipmi-type is not set
for SSIF interfaces, as it is not necessary for that.

Fixes: 3cd83bac ("ipmi: Consolidate the adding of platform devices")
Reported-by: Kamlakant Patel <kamlakantp@marvell.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: stable@vger.kernel.org # 5.1

There is a spelling mistake in the documentation. Fix it.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Message-Id: <20190418101502.9748-1-colin.king@canonical.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

This causes a link failure on ARM in certain configurations,
when we reference each atomic operation from .alt.smp.init in
order to patch out atomics on non-SMP systems:

`.exit.text' referenced in section `.alt.smp.init' of drivers/char/ipmi/ipmi_msghandler.o: defined in discarded section `.exit.text' of drivers/char/ipmi/ipmi_msghandler.o

In this case, we can trivially replace the atomic_inc() with
an atomic_set() that has the same effect and does not require
a fixup.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Message-Id: <20190415155509.3565087-1-arnd@arndb.de>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

It's not used by anything, so just get rid of it.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

The "init_name" variable isn't used any more after commit 90b2d4f1
("ipmi_si: Remove hacks for adding a dummy platform devices").
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Message-Id: <20190322065426.GB12551@kadam>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

Fix sparse warning:

drivers/char/ipmi/ipmi_msghandler.c:635:20: warning:
 symbol 'ipmi_interfaces_srcu' was not declared. Should it be static?
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Message-Id: <20190320133505.21984-1-yuehaibing@huawei.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

Pull IPMI fixes from Corey Minyard:
 "Fixes for some bugs cause by recent changes. One crash if you feed bad
  data to the module parameters, one BUG that sometimes occurs when a
  user closes the connection, and one bug that cause the driver to not
  work if the configuration information only comes in from SMBIOS"

* tag 'for-linus-5.1-2' of git://github.com/cminyard/linux-ipmi:
  ipmi: fix sleep-in-atomic in free_user at cleanup SRCU user->release_barrier
  ipmi: ipmi_si_hardcode.c: init si_type array to fix a crash
  ipmi: Fix failure on SMBIOS specified devices

Pull networking fixes from David Miller:

 1) Handle init flow failures properly in iwlwifi driver, from Shahar S
    Matityahu.

 2) mac80211 TXQs need to be unscheduled on powersave start, from Felix
    Fietkau.

 3) SKB memory accounting fix in A-MDSU aggregation, from Felix Fietkau.

 4) Increase RCU lock hold time in mlx5 FPGA code, from Saeed Mahameed.

 5) Avoid checksum complete with XDP in mlx5, also from Saeed.

 6) Fix netdev feature clobbering in ibmvnic driver, from Thomas Falcon.

 7) Partial sent TLS record leak fix from Jakub Kicinski.

 8) Reject zero size iova range in vhost, from Jason Wang.

 9) Allow pending work to complete before clcsock release from Karsten
    Graul.

10) Fix XDP handling max MTU in thunderx, from Matteo Croce.

11) A lot of protocols look at the sa_family field of a sockaddr before
    validating it's length is large enough, from Tetsuo Handa.

12) Don't write to free'd pointer in qede ptp error path, from Colin Ian
    King.

13) Have to recompile IP options in ipv4_link_failure because it can be
    invoked from ARP, from Stephen Suryaputra.

14) Doorbell handling fixes in qed from Denis Bolotin.

15) Revert net-sysfs kobject register leak fix, it causes new problems.
    From Wang Hai.

16) Spectre v1 fix in ATM code, from Gustavo A. R. Silva.

17) Fix put of BROPT_VLAN_STATS_PER_PORT in bridging code, from Nikolay
    Aleksandrov.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (111 commits)
  socket: fix compat SO_RCVTIMEO_NEW/SO_SNDTIMEO_NEW
  tcp: tcp_grow_window() needs to respect tcp_space()
  ocelot: Clean up stats update deferred work
  ocelot: Don't sleep in atomic context (irqs_disabled())
  net: bridge: fix netlink export of vlan_stats_per_port option
  qed: fix spelling mistake "faspath" -> "fastpath"
  tipc: set sysctl_tipc_rmem and named_timeout right range
  tipc: fix link established but not in session
  net: Fix missing meta data in skb with vlan packet
  net: atm: Fix potential Spectre v1 vulnerabilities
  net/core: work around section mismatch warning for ptp_classifier
  net: bridge: fix per-port af_packet sockets
  bnx2x: fix spelling mistake "dicline" -> "decline"
  route: Avoid crash from dereferencing NULL rt->from
  MAINTAINERS: normalize Woojung Huh's email address
  bonding: fix event handling for stacked bonds
  Revert "net-sysfs: Fix memory leak in netdev_register_kobject"
  rtnetlink: fix rtnl_valid_stats_req() nlmsg_len check
  qed: Fix the DORQ's attentions handling
  qed: Fix missing DORQ attentions
  ...

free_user() could be called in atomic context.

This patch pushed the free operation off into a workqueue.

Example:

 BUG: sleeping function called from invalid context at kernel/workqueue.c:2856
 in_atomic(): 1, irqs_disabled(): 0, pid: 177, name: ksoftirqd/27
 CPU: 27 PID: 177 Comm: ksoftirqd/27 Not tainted 4.19.25-3 #1
 Hardware name: AIC 1S-HV26-08/MB-DPSB04-06, BIOS IVYBV060 10/21/2015
 Call Trace:
  dump_stack+0x5c/0x7b
  ___might_sleep+0xec/0x110
  __flush_work+0x48/0x1f0
  ? try_to_del_timer_sync+0x4d/0x80
  _cleanup_srcu_struct+0x104/0x140
  free_user+0x18/0x30 [ipmi_msghandler]
  ipmi_free_recv_msg+0x3a/0x50 [ipmi_msghandler]
  deliver_response+0xbd/0xd0 [ipmi_msghandler]
  deliver_local_response+0xe/0x30 [ipmi_msghandler]
  handle_one_recv_msg+0x163/0xc80 [ipmi_msghandler]
  ? dequeue_entity+0xa0/0x960
  handle_new_recv_msgs+0x15c/0x1f0 [ipmi_msghandler]
  tasklet_action_common.isra.22+0x103/0x120
  __do_softirq+0xf8/0x2d7
  run_ksoftirqd+0x26/0x50
  smpboot_thread_fn+0x11d/0x1e0
  kthread+0x103/0x140
  ? sort_range+0x20/0x20
  ? kthread_destroy_worker+0x40/0x40
  ret_from_fork+0x1f/0x40

Fixes: 77f82696 ("ipmi: fix use-after-free of user->release_barrier.rda")
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: stable@vger.kernel.org # 5.0
Cc: Yang Yingliang <yangyingliang@huawei.com>

It looks like the new socket options only work correctly
for native execution, but in case of compat mode fall back
to the old behavior as we ignore the 'old_timeval' flag.

Rework so we treat SO_RCVTIMEO_NEW/SO_SNDTIMEO_NEW the
same way in compat and native 32-bit mode.

Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Fixes: a9beb86a ("sock: Add SO_RCVTIMEO_NEW and SO_SNDTIMEO_NEW")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

For some reason, tcp_grow_window() correctly tests if enough room
is present before attempting to increase tp->rcv_ssthresh,
but does not prevent it to grow past tcp_space()

This is causing hard to debug issues, like failing
the (__tcp_select_window(sk) >= tp->rcv_wnd) test
in __tcp_ack_snd_check(), causing ACK delays and possibly
slow flows.

Depending on tcp_rmem[2], MTU, skb->len/skb->truesize ratio,
we can see the problem happening on "netperf -t TCP_RR -- -r 2000,2000"
after about 60 round trips, when the active side no longer sends
immediate acks.

This bug predates git history.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This is preventive cleanup that may save troubles later.
No need to cancel repeateadly queued work if code is properly
refactored.
Don't let the ethtool -s process interfere with the stat workqueue
scheduling.
Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Preemption disabled at:
 [<ffff000008cabd54>] dev_set_rx_mode+0x1c/0x38
 Call trace:
 [<ffff00000808a5c0>] dump_backtrace+0x0/0x3d0
 [<ffff00000808a9a4>] show_stack+0x14/0x20
 [<ffff000008e6c0c0>] dump_stack+0xac/0xe4
 [<ffff0000080fe76c>] ___might_sleep+0x164/0x238
 [<ffff0000080fe890>] __might_sleep+0x50/0x88
 [<ffff0000082261e4>] kmem_cache_alloc+0x17c/0x1d0
 [<ffff000000ea0ae8>] ocelot_set_rx_mode+0x108/0x188 [mscc_ocelot_common]
 [<ffff000008cabcf0>] __dev_set_rx_mode+0x58/0xa0
 [<ffff000008cabd5c>] dev_set_rx_mode+0x24/0x38

Fixes: a556c76a ("net: mscc: Add initial Ocelot switch support")
Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Since the introduction of the vlan_stats_per_port option the netlink
export of it has been broken since I made a typo and used the ifla
attribute instead of the bridge option to retrieve its state.
Sysfs export is fine, only netlink export has been affected.

Fixes: 9163a0fc ("net: bridge: add support for per-port vlan stats")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There is a spelling mistake in a DP_INFO message, fix it.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

We find that sysctl_tipc_rmem and named_timeout do not have the right minimum
setting. sysctl_tipc_rmem should be larger than zero, like sysctl_tcp_rmem.
And named_timeout as a timeout setting should be not less than zero.

Fixes: cc79dd1b ("tipc: change socket buffer overflow control to respect sk_rcvbuf")
Fixes: a5325ae5 ("tipc: add name distributor resiliency queue")
Signed-off-by: Jie Liu <liujie165@huawei.com>
Reported-by: Qiang Ning <ningqiang1@huawei.com>
Reviewed-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

According to the link FSM, when a link endpoint got RESET_MSG (- a
traditional one without the stopping bit) from its peer, it moves to
PEER_RESET state and raises a LINK_DOWN event which then resets the
link itself. Its state will become ESTABLISHING after the reset event
and the link will be re-established soon after this endpoint starts to
send ACTIVATE_MSG to the peer.

There is no problem with this mechanism, however the link resetting has
cleared the link 'in_session' flag (along with the other important link
data such as: the link 'mtu') that was correctly set up at the 1st step
(i.e. when this endpoint received the peer RESET_MSG). As a result, the
link will become ESTABLISHED, but the 'in_session' flag is not set, and
all STATE_MSG from its peer will be dropped at the link_validate_msg().
It means the link not synced and will sooner or later face a failure.

Since the link reset action is obviously needed for a new link session
(this is also true in the other situations), the problem here is that
the link is re-established a bit too early when the link endpoints are
not really in-sync yet. The commit forces a resync as already done in
the previous commit 91986ee1 ("tipc: fix link session and
re-establish issues") by simply varying the link 'peer_session' value
at the link_reset().
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

skb_reorder_vlan_header() should move XDP meta data with ethernet header
if XDP meta data exists.

Fixes: de8f3a83 ("bpf: add meta pointer for direct access")
Signed-off-by: Yuya Kusakabe <yuya.kusakabe@gmail.com>
Signed-off-by: Takeru Hayasaka <taketarou2@gmail.com>
Co-developed-by: Takeru Hayasaka <taketarou2@gmail.com>
Reviewed-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

arg is controlled by user-space, hence leading to a potential
exploitation of the Spectre variant 1 vulnerability.

This issue was detected with the help of Smatch:

net/atm/lec.c:715 lec_mcast_attach() warn: potential spectre issue 'dev_lec' [r] (local cap)

Fix this by sanitizing arg before using it to index dev_lec.

Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].

[1] https://lore.kernel.org/lkml/20180423164740.GY17484@dhcp22.suse.cz/Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The routine ptp_classifier_init() uses an initializer for an
automatic struct type variable which refers to an __initdata
symbol. This is perfectly legal, but may trigger a section
mismatch warning when running the compiler in -fpic mode, due
to the fact that the initializer may be emitted into an anonymous
.data section thats lack the __init annotation. So work around it
by using assignments instead.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When the commit below was introduced it changed two visible things:
 - the skb was no longer passed through the protocol handlers with the
   original device
 - the skb was passed up the stack with skb->dev = bridge

The first change broke af_packet sockets on bridge ports. For example we
use them for hostapd which listens for ETH_P_PAE packets on the ports.
We discussed two possible fixes:
 - create a clone and pass it through NF_HOOK(), act on the original skb
   based on the result
 - somehow signal to the caller from the okfn() that it was called,
   meaning the skb is ok to be passed, which this patch is trying to
   implement via returning 1 from the bridge link-local okfn()

Note that we rely on the fact that NF_QUEUE/STOLEN would return 0 and
drop/error would return < 0 thus the okfn() is called only when the
return was 1, so we signal to the caller that it was called by preserving
the return value from nf_hook().

Fixes: 8626c56c ("bridge: fix potential use-after-free when hook returns QUEUE or STOLEN verdict")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The intended behavior of function ipmi_hardcode_init_one() is to default
to kcs interface when no type argument is presented when initializing
ipmi with hard coded addresses.

However, the array of char pointers allocated on the stack by function
ipmi_hardcode_init() was not inited to zeroes, so it contained stack
debris.

Consequently, passing the cruft stored in this array to function
ipmi_hardcode_init_one() caused a crash when it was unable to detect
that the char * being passed was nonsense and tried to access the
address specified by the bogus pointer.

The fix is simply to initialize the si_type array to zeroes, so if
there were no type argument given to at the command line, function
ipmi_hardcode_init_one() could properly default to the kcs interface.
Signed-off-by: Tony Camuso <tcamuso@redhat.com>
Message-Id: <1554837603-40299-1-git-send-email-tcamuso@redhat.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

An extra memset was put into a place that cleared the interface
type.
Reported-by: Tony Camuso <tcamuso@redhat.com>
Fixes: 3cd83bac ("ipmi: Consolidate the adding of platform devices")
Signed-off-by: Corey Minyard <cminyard@mvista.com>

Merge tag 'riscv-for-linus-5.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux

Pull RISC-V fixes from Palmer Dabbelt:
 "This contains an assortment of RISC-V-related fixups that we found
  after rc4. They're all really unrelated:

   - The addition of a 32-bit defconfig, to emphasize testing the 32-bit
     port.

   - A device tree bindings patch, which is pre-work for some patches
     that target 5.2.

   - A fix to support booting on systems with more physical memory than
     the maximum supported by the kernel"

* tag 'riscv-for-linus-5.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux:
  RISC-V: Fix Maximum Physical Memory 2GiB option for 64bit systems
  dt-bindings: clock: sifive: add FU540-C000 PRCI clock constants
  RISC-V: Add separate defconfig for 32bit systems

Pull KVM fixes from Paolo Bonzini:
 "5.1 keeps its reputation as a big bugfix release for KVM x86.

   - Fix for a memory leak introduced during the merge window

   - Fixes for nested VMX with ept=0

   - Fixes for AMD (APIC virtualization, NMI injection)

   - Fixes for Hyper-V under KVM and KVM under Hyper-V

   - Fixes for 32-bit SMM and tests for SMM virtualization

   - More array_index_nospec peppering"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (21 commits)
  KVM: x86: avoid misreporting level-triggered irqs as edge-triggered in tracing
  KVM: fix spectrev1 gadgets
  KVM: x86: fix warning Using plain integer as NULL pointer
  selftests: kvm: add a selftest for SMM
  selftests: kvm: fix for compilers that do not support -no-pie
  selftests: kvm/evmcs_test: complete I/O before migrating guest state
  KVM: x86: Always use 32-bit SMRAM save state for 32-bit kernels
  KVM: x86: Don't clear EFER during SMM transitions for 32-bit vCPU
  KVM: x86: clear SMM flags before loading state while leaving SMM
  KVM: x86: Open code kvm_set_hflags
  KVM: x86: Load SMRAM in a single shot when leaving SMM
  KVM: nVMX: Expose RDPMC-exiting only when guest supports PMU
  KVM: x86: Raise #GP when guest vCPU do not support PMU
  x86/kvm: move kvm_load/put_guest_xcr0 into atomic context
  KVM: x86: svm: make sure NMI is injected after nmi_singlestep
  svm/avic: Fix invalidate logical APIC id entry
  Revert "svm: Fix AVIC incomplete IPI emulation"
  kvm: mmu: Fix overflow on kvm mmu page limit calculation
  KVM: nVMX: always use early vmcs check when EPT is disabled
  KVM: nVMX: allow tests to use bad virtual-APIC page address
  ...

In __apic_accept_irq() interface trig_mode is int and actually on some code
paths it is set above u8:

kvm_apic_set_irq() extracts it from 'struct kvm_lapic_irq' where trig_mode
is u16. This is done on purpose as e.g. kvm_set_msi_irq() sets it to
(1 << 15) & e->msi.data

kvm_apic_local_deliver sets it to reg & (1 << 15).

Fix the immediate issue by making 'tm' into u16. We may also want to adjust
__apic_accept_irq() interface and use proper sizes for vector, level,
trig_mode but this is not urgent.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

These were found with smatch, and then generalized when applicable.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Changed passing argument as "0 to NULL" which resolves below sparse warning

arch/x86/kvm/x86.c:3096:61: warning: Using plain integer as NULL pointer
Signed-off-by: Hariprasad Kelam <hariprasad.kelam@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Add a simple test for SMM, based on VMX.  The test implements its own
sync between the guest and the host as using our ucall library seems to
be too cumbersome: SMI handler is happening in real-address mode.

This patch also fixes KVM_SET_NESTED_STATE to happen after
KVM_SET_VCPU_EVENTS, in fact it places it last.  This is because
KVM needs to know whether the processor is in SMM or not.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

-no-pie was added to GCC at the same time as their configuration option
--enable-default-pie.  Compilers that were built before do not have
-no-pie, but they also do not need it.  Detect the option at build
time.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Starting state migration after an IO exit without first completing IO
may result in test failures.  We already have two tests that need this
(this patch in fact fixes evmcs_test, similar to what was fixed for
state_test in commit 0f73bbc8, "KVM: selftests: complete IO before
migrating guest state", 2019-03-13) and a third is coming.  So, move the
code to vcpu_save_state, and while at it do not access register state
until after I/O is complete.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Invoking the 64-bit variation on a 32-bit kenrel will crash the guest,
trigger a WARN, and/or lead to a buffer overrun in the host, e.g.
rsm_load_state_64() writes r8-r15 unconditionally, but enum kvm_reg and
thus x86_emulate_ctxt._regs only define r8-r15 for CONFIG_X86_64.

KVM allows userspace to report long mode support via CPUID, even though
the guest is all but guaranteed to crash if it actually tries to enable
long mode.  But, a pure 32-bit guest that is ignorant of long mode will
happily plod along.

SMM complicates things as 64-bit CPUs use a different SMRAM save state
area.  KVM handles this correctly for 64-bit kernels, e.g. uses the
legacy save state map if userspace has hid long mode from the guest,
but doesn't fare well when userspace reports long mode support on a
32-bit host kernel (32-bit KVM doesn't support 64-bit guests).

Since the alternative is to crash the guest, e.g. by not loading state
or explicitly requesting shutdown, unconditionally use the legacy SMRAM
save state map for 32-bit KVM.  If a guest has managed to get far enough
to handle SMIs when running under a weird/buggy userspace hypervisor,
then don't deliberately crash the guest since there are no downsides
(from KVM's perspective) to allow it to continue running.

Fixes: 660a5d51 ("KVM: x86: save/load state on SMM switch")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Neither AMD nor Intel CPUs have an EFER field in the legacy SMRAM save
state area, i.e. don't save/restore EFER across SMM transitions.  KVM
somewhat models this, e.g. doesn't clear EFER on entry to SMM if the
guest doesn't support long mode.  But during RSM, KVM unconditionally
clears EFER so that it can get back to pure 32-bit mode in order to
start loading CRs with their actual non-SMM values.

Clear EFER only when it will be written when loading the non-SMM state
so as to preserve bits that can theoretically be set on 32-bit vCPUs,
e.g. KVM always emulates EFER_SCE.

And because CR4.PAE is cleared only to play nice with EFER, wrap that
code in the long mode check as well.  Note, this may result in a
compiler warning about cr4 being consumed uninitialized.  Re-read CR4
even though it's technically unnecessary, as doing so allows for more
readable code and RSM emulation is not a performance critical path.

Fixes: 660a5d51 ("KVM: x86: save/load state on SMM switch")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

RSM emulation is currently broken on VMX when the interrupted guest has
CR4.VMXE=1.  Stop dancing around the issue of HF_SMM_MASK being set when
loading SMSTATE into architectural state, e.g. by toggling it for
problematic flows, and simply clear HF_SMM_MASK prior to loading
architectural state (from SMRAM save state area).
Reported-by: Jon Doron <arilou@gmail.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Fixes: 5bea5123 ("KVM: VMX: check nested state and CR4.VMXE against SMM")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Prepare for clearing HF_SMM_MASK prior to loading state from the SMRAM
save state map, i.e. kvm_smm_changed() needs to be called after state
has been loaded and so cannot be done automatically when setting
hflags from RSM.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

RSM emulation is currently broken on VMX when the interrupted guest has
CR4.VMXE=1.  Rather than dance around the issue of HF_SMM_MASK being set
when loading SMSTATE into architectural state, ideally RSM emulation
itself would be reworked to clear HF_SMM_MASK prior to loading non-SMM
architectural state.

Ostensibly, the only motivation for having HF_SMM_MASK set throughout
the loading of state from the SMRAM save state area is so that the
memory accesses from GET_SMSTATE() are tagged with role.smm.  Load
all of the SMRAM save state area from guest memory at the beginning of
RSM emulation, and load state from the buffer instead of reading guest
memory one-by-one.

This paves the way for clearing HF_SMM_MASK prior to loading state,
and also aligns RSM with the enter_smm() behavior, which fills a
buffer and writes SMRAM save state in a single go.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Issue was discovered when running kvm-unit-tests on KVM running as L1 on
top of Hyper-V.

When vmx_instruction_intercept unit-test attempts to run RDPMC to test
RDPMC-exiting, it is intercepted by L1 KVM which it's EXIT_REASON_RDPMC
handler raise #GP because vCPU exposed by Hyper-V doesn't support PMU.
Instead of unit-test expectation to be reflected with EXIT_REASON_RDPMC.

The reason vmx_instruction_intercept unit-test attempts to run RDPMC
even though Hyper-V doesn't support PMU is because L1 expose to L2
support for RDPMC-exiting. Which is reasonable to assume that is
supported only in case CPU supports PMU to being with.

Above issue can easily be simulated by modifying
vmx_instruction_intercept config in x86/unittests.cfg to run QEMU with
"-cpu host,+vmx,-pmu" and run unit-test.

To handle issue, change KVM to expose RDPMC-exiting only when guest
supports PMU.
Reported-by: Saar Amar <saaramar@microsoft.com>
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Before this change, reading a VMware pseduo PMC will succeed even when
PMU is not supported by guest. This can easily be seen by running
kvm-unit-test vmware_backdoors with "-cpu host,-pmu" option.
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

guest xcr0 could leak into host when MCE happens in guest mode. Because
do_machine_check() could schedule out at a few places.

For example:

kvm_load_guest_xcr0
...
kvm_x86_ops->run(vcpu) {
  vmx_vcpu_run
    vmx_complete_atomic_exit
      kvm_machine_check
        do_machine_check
          do_memory_failure
            memory_failure
              lock_page

In this case, host_xcr0 is 0x2ff, guest vcpu xcr0 is 0xff. After schedule
out, host cpu has guest xcr0 loaded (0xff).

In __switch_to {
     switch_fpu_finish
       copy_kernel_to_fpregs
         XRSTORS

If any bit i in XSTATE_BV[i] == 1 and xcr0[i] == 0, XRSTORS will
generate #GP (In this case, bit 9). Then ex_handler_fprestore kicks in
and tries to reinitialize fpu by restoring init fpu state. Same story as
last #GP, except we get DOUBLE FAULT this time.

Cc: stable@vger.kernel.org
Signed-off-by: WANG Chao <chao.wang@ucloud.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>