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Filename Latest commit message Latest commit date
Maxim Levitsky d239c08f09 kvm: x86: replace kvm_spec_ctrl_test_value with runtime test on the host
commit 841c2be09fe4f495fe5224952a419bd8c7e5b455 upstream.

To avoid complex and in some cases incorrect logic in
kvm_spec_ctrl_test_value, just try the guest's given value on the host
processor instead, and if it doesn't #GP, allow the guest to set it.

One such case is when host CPU supports STIBP mitigation
but doesn't support IBRS (as is the case with some Zen2 AMD cpus),
and in this case we were giving guest #GP when it tried to use STIBP

The reason why can can do the host test is that IA32_SPEC_CTRL msr is
passed to the guest, after the guest sets it to a non zero value
for the first time (due to performance reasons),
and as as result of this, it is pointless to emulate #GP condition on
this first access, in a different way than what the host CPU does.

This is based on a patch from Sean Christopherson, who suggested this idea.

Fixes: 6441fa6178f5 ("KVM: x86: avoid incorrect writes to host MSR_IA32_SPEC_CTRL")
Cc: stable@vger.kernel.org
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20200708115731.180097-1-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-04 10:26:09 +01:00
arch kvm: x86: replace kvm_spec_ctrl_test_value with runtime test on the host 2021-03-04 10:26:09 +01:00
block bfq-iosched: Revert "bfq: Fix computation of shallow depth" 2021-02-17 10:35:16 +01:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto crypto: asym_tpm: correct zero out potential secrets 2021-01-12 20:16:17 +01:00
Documentation KVM: Forbid the use of tagged userspace addresses for memslots 2021-02-03 23:25:57 +01:00
drivers cxgb4: Add new T6 PCI device id 0x6092 2021-02-26 10:10:28 +01:00
fs cifs: Set CIFS_MOUNT_USE_PREFIX_PATH flag on setting cifs_sb->prepath. 2021-02-26 10:10:28 +01:00
include vmlinux.lds.h: add DWARF v5 sections 2021-03-04 10:26:09 +01:00
init fgraph: Initialize tracing_graph_pause at task creation 2021-02-10 09:25:29 +01:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel bpf: Fix truncation handling for mod32 dst reg wrt zero 2021-02-26 10:10:26 +01:00
lib udp: fix skb_copy_and_csum_datagram with odd segment sizes 2021-02-17 10:35:19 +01:00
LICENSES
mm mm: provide a saner PTE walking API for modules 2021-02-26 10:10:28 +01:00
net net: bridge: Fix a warning when del bridge sysfs 2021-02-23 15:02:25 +01:00
samples samples: bpf: Fix lwt_len_hist reusing previous BPF map 2020-12-30 11:51:12 +01:00
scripts scripts/recordmcount.pl: support big endian for ARCH sh 2021-02-26 10:10:28 +01:00
security cap: fix conversions on getxattr 2021-02-17 10:35:15 +01:00
sound ASoC: ak4458: correct reset polarity 2021-02-13 13:52:55 +01:00
tools selftests: txtimestamp: fix compilation issue 2021-02-17 10:35:17 +01:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: Use kvm_pfn_t for local PFN variable in hva_to_pfn_remapped() 2021-02-26 10:10:28 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.101 2021-02-26 10:10:28 +01:00
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.