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Filename Latest commit message Latest commit date
Sean Christopherson f93f7ede08 Revert "KVM: nVMX: Expose RDPMC-exiting only when guest supports PMU"
The RDPMC-exiting control is dependent on the existence of the RDPMC
instruction itself, i.e. is not tied to the "Architectural Performance
Monitoring" feature.  For all intents and purposes, the control exists
on all CPUs with VMX support since RDPMC also exists on all VCPUs with
VMX supported.  Per Intel's SDM:

  The RDPMC instruction was introduced into the IA-32 Architecture in
  the Pentium Pro processor and the Pentium processor with MMX technology.
  The earlier Pentium processors have performance-monitoring counters, but
  they must be read with the RDMSR instruction.

Because RDPMC-exiting always exists, KVM requires the control and refuses
to load if it's not available.  As a result, hiding the PMU from a guest
breaks nested virtualization if the guest attemts to use KVM.

While it's not explicitly stated in the RDPMC pseudocode, the VM-Exit
check for RDPMC-exiting follows standard fault vs. VM-Exit prioritization
for privileged instructions, e.g. occurs after the CPL/CR0.PE/CR4.PCE
checks, but before the counter referenced in ECX is checked for validity.

In other words, the original KVM behavior of injecting a #GP was correct,
and the KVM unit test needs to be adjusted accordingly, e.g. eat the #GP
when the unit test guest (L3 in this case) executes RDPMC without
RDPMC-exiting set in the unit test host (L2).

This reverts commit e51bfdb687.

Fixes: e51bfdb687 ("KVM: nVMX: Expose RDPMC-exiting only when guest supports PMU")
Reported-by: David Hill <hilld@binarystorm.net>
Cc: Saar Amar <saaramar@microsoft.com>
Cc: Mihai Carabas <mihai.carabas@oracle.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-05-15 23:19:19 +02:00
arch Revert "KVM: nVMX: Expose RDPMC-exiting only when guest supports PMU" 2019-05-15 23:19:19 +02:00
block block: Revert v5.0 blk_mq_request_issue_directly() changes 2019-04-05 09:40:46 -06:00
certs
crypto lib/lzo: separate lzo-rle from lzo 2019-03-07 18:32:03 -08:00
Documentation KVM: Introduce KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 2019-05-08 13:48:24 +02:00
drivers Bluetooth: btusb: request wake pin with NOAUTOEN 2019-04-09 17:38:24 -10:00
fs Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-04-09 16:20:59 -10:00
include KVM: Introduce KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 2019-05-08 13:48:24 +02:00
init init/main: add checks for the return value of memblock_alloc*() 2019-03-12 10:04:02 -07:00
ipc Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 14:08:19 -07:00
kernel Merge branch 'akpm' (patches from Andrew) 2019-04-05 17:08:55 -10:00
lib Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-04-09 16:20:59 -10:00
LICENSES
mm slab: fix a crash by reading /proc/slab_allocators 2019-04-07 19:23:12 -10:00
net net: ip6_gre: fix possible use-after-free in ip6erspan_rcv 2019-04-08 16:16:47 -07:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-03-11 08:54:01 -07:00
scripts fs: stream_open - opener for stream-like files so that read and write can run simultaneously without deadlock 2019-04-06 07:01:55 -10:00
security KEYS: trusted: fix -Wvarags warning 2019-04-08 15:58:54 -07:00
sound sound fixes for 5.1-rc3 2019-03-29 14:53:33 -07:00
tools tests: kvm: Add tests for KVM_SET_NESTED_STATE 2019-05-08 14:12:09 +02:00
usr
virt KVM: Introduce KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 2019-05-08 13:48:24 +02:00
.clang-format Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 13:43:42 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap Update Nicolas Pitre's email address 2019-04-02 18:12:44 -10:00
COPYING
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-08 17:10:46 -10:00
Makefile Linux 5.1-rc4 2019-04-07 14:09:59 -10:00
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.