No description
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Sean Christopherson e40bde8a28 KVM: nVMX: Snapshot pre-VM-Enter DEBUGCTL for !nested_run_pending case
commit 764643a6be07445308e492a528197044c801b3ba upstream.

If a nested run isn't pending, snapshot vmcs01.GUEST_IA32_DEBUGCTL
irrespective of whether or not VM_ENTRY_LOAD_DEBUG_CONTROLS is set in
vmcs12.  When restoring nested state, e.g. after migration, without a
nested run pending, prepare_vmcs02() will propagate
nested.vmcs01_debugctl to vmcs02, i.e. will load garbage/zeros into
vmcs02.GUEST_IA32_DEBUGCTL.

If userspace restores nested state before MSRs, then loading garbage is a
non-issue as loading DEBUGCTL will also update vmcs02.  But if usersepace
restores MSRs first, then KVM is responsible for propagating L2's value,
which is actually thrown into vmcs01, into vmcs02.

Restoring L2 MSRs into vmcs01, i.e. loading all MSRs before nested state
is all kinds of bizarre and ideally would not be supported.  Sadly, some
VMMs do exactly that and rely on KVM to make things work.

Note, there's still a lurking SMM bug, as propagating vmcs01's DEBUGCTL
to vmcs02 across RSM may corrupt L2's DEBUGCTL.  But KVM's entire VMX+SMM
emulation is flawed as SMI+RSM should not toouch _any_ VMCS when use the
"default treatment of SMIs", i.e. when not using an SMI Transfer Monitor.

Link: https://lore.kernel.org/all/Yobt1XwOfb5M6Dfa@google.com
Fixes: 8fcc4b5923 ("kvm: nVMX: Introduce KVM_CAP_NESTED_STATE")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220614215831.3762138-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-25 11:17:19 +02:00
arch KVM: nVMX: Snapshot pre-VM-Enter DEBUGCTL for !nested_run_pending case 2022-08-25 11:17:19 +02:00
block
certs
crypto
Documentation x86/speculation: Add RSB VM Exit protections 2022-08-11 12:57:53 +02:00
drivers HID: wacom: Don't register pad_input for touch switch 2022-08-25 11:17:19 +02:00
fs ntfs: fix use-after-free in ntfs_ucsncmp() 2022-08-03 11:59:37 +02:00
include add barriers to buffer_uptodate and set_buffer_uptodate 2022-08-25 11:17:18 +02:00
init
ipc
kernel bpf: Verifer, adjust_scalar_min_max_vals to always call update_reg_bounds() 2022-08-11 12:57:51 +02:00
lib locking/refcount: Consolidate implementations of refcount_t 2022-07-29 17:14:17 +02:00
LICENSES
mm mm/mempolicy: fix uninit-value in mpol_rebind_policy() 2022-07-29 17:14:16 +02:00
net sctp: leave the err path free in sctp_stream_init to sctp_stream_free 2022-08-03 11:59:41 +02:00
samples
scripts modpost: fix section mismatch check for exported init/exit sections 2022-06-29 08:58:49 +02:00
security ima: remove the IMA_TEMPLATE Kconfig option 2022-07-29 17:14:16 +02:00
sound ALSA: bcd2000: Fix a UAF bug on the error path of probing 2022-08-25 11:17:17 +02:00
tools x86/speculation: Add RSB VM Exit protections 2022-08-11 12:57:53 +02:00
usr
virt KVM: Don't null dereference ops->destroy 2022-08-11 12:57:52 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Makefile: link with -z noexecstack --no-warn-rwx-segments 2022-08-25 11:17:17 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.