Go to file
Sean Christopherson 0c7a98e34d KVM: x86/mmu: WARN on an invalid root_hpa
WARN on the existing invalid root_hpa checks in __direct_map() and
FNAME(fetch).  The "legitimate" path that invalidated root_hpa in the
middle of a page fault is long since gone, i.e. it should no longer be
impossible to invalidate in the middle of a page fault[*].

The root_hpa checks were added by two related commits

  989c6b34f6 ("KVM: MMU: handle invalid root_hpa at __direct_map")
  37f6a4e237 ("KVM: x86: handle invalid root_hpa everywhere")

to fix a bug where nested_vmx_vmexit() could be called *in the middle*
of a page fault.  At the time, vmx_interrupt_allowed(), which was and
still is used by kvm_can_do_async_pf() via ->interrupt_allowed(),
directly invoked nested_vmx_vmexit() to switch from L2 to L1 to emulate
a VM-Exit on a pending interrupt.  Emulating the nested VM-Exit resulted
in root_hpa being invalidated by kvm_mmu_reset_context() without
explicitly terminating the page fault.

Now that root_hpa is checked for validity by kvm_mmu_page_fault(), WARN
on an invalid root_hpa to detect any flows that reset the MMU while
handling a page fault.  The broken vmx_interrupt_allowed() behavior has
long since been fixed and resetting the MMU during a page fault should
not be considered legal behavior.

[*] It's actually technically possible in FNAME(page_fault)() because it
    calls inject_page_fault() when the guest translation is invalid, but
    in that case the page fault handling is immediately terminated.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-08 18:16:08 +01:00
arch KVM: x86/mmu: WARN on an invalid root_hpa 2020-01-08 18:16:08 +01:00
block block: fix splitting segments on boundary masks 2019-12-30 08:51:18 -07:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto tpmdd fixes for Linux v5.5-rc3 2019-12-18 17:17:36 -08:00
Documentation RISC-V updates for v5.5-rc5 2020-01-05 11:15:31 -08:00
drivers RISC-V updates for v5.5-rc5 2020-01-05 11:15:31 -08:00
fs ocfs2: fix the crash due to call ocfs2_get_dlm_debug once less 2020-01-04 13:55:09 -08:00
include KVM: x86: Use gpa_t for cr2/gpa to fix TDP support on 32-bit KVM 2020-01-08 18:16:02 +01:00
init Revert "fs: remove ksys_dup()" 2020-01-02 16:15:33 -08:00
ipc treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
kernel memcg: account security cred as well to kmemcg 2020-01-04 13:55:09 -08:00
lib Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-12-22 17:00:04 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/hugetlb: defer freeing of huge pages if in non-task context 2020-01-04 13:55:09 -08:00
net hsr: fix slab-out-of-bounds Read in hsr_debugfs_rename() 2019-12-30 20:36:27 -08:00
samples samples/seccomp: Zero out members based on seccomp_notif_sizes 2020-01-02 13:03:39 -08:00
scripts Kbuild fixes for v5.5 (2nd) 2020-01-03 11:21:25 -08:00
security + Bug fixes 2020-01-04 19:28:30 -08:00
sound sound fixes for 5.5-rc5 2020-01-03 11:10:31 -08:00
tools KVM: VMX: Fix the spelling of CPU_BASED_USE_TSC_OFFSETTING 2020-01-08 18:15:59 +01:00
usr gen_initramfs_list.sh: fix 'bad variable name' error 2020-01-04 00:00:48 +09:00
virt KVM: x86: Use gpa_t for cr2/gpa to fix TDP support on 32-bit KVM 2020-01-08 18:16:02 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore modpost: dump missing namespaces into a single modules.nsdeps file 2019-11-11 20:10:01 +09:00
.mailmap Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-12-22 09:54:33 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Linux 5.4-rc4 2019-10-29 04:43:29 -06:00
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 RISC-V updates for v5.5-rc5 2020-01-05 11:15:31 -08:00
Makefile Linux 5.5-rc5 2020-01-05 14:23:27 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.