For the duration of mapping eVMCS, it derefences ->memslots without holding
->srcu or ->slots_lock when accessing hv assist page. This patch fixes it by
moving nested_sync_vmcs12_to_shadow to prepare_guest_switch, where the SRCU
is already taken.

It can be reproduced by running kvm's evmcs_test selftest.

  =============================
  warning: suspicious rcu usage
  5.6.0-rc1+ #53 tainted: g        w ioe
  -----------------------------
  ./include/linux/kvm_host.h:623 suspicious rcu_dereference_check() usage!

  other info that might help us debug this:

   rcu_scheduler_active = 2, debug_locks = 1
  1 lock held by evmcs_test/8507:
   #0: ffff9ddd156d00d0 (&vcpu->mutex){+.+.}, at:
kvm_vcpu_ioctl+0x85/0x680 [kvm]

  stack backtrace:
  cpu: 6 pid: 8507 comm: evmcs_test tainted: g        w ioe     5.6.0-rc1+ #53
  hardware name: dell inc. optiplex 7040/0jctf8, bios 1.4.9 09/12/2016
  call trace:
   dump_stack+0x68/0x9b
   kvm_read_guest_cached+0x11d/0x150 [kvm]
   kvm_hv_get_assist_page+0x33/0x40 [kvm]
   nested_enlightened_vmentry+0x2c/0x60 [kvm_intel]
   nested_vmx_handle_enlightened_vmptrld.part.52+0x32/0x1c0 [kvm_intel]
   nested_sync_vmcs12_to_shadow+0x439/0x680 [kvm_intel]
   vmx_vcpu_run+0x67a/0xe60 [kvm_intel]
   vcpu_enter_guest+0x35e/0x1bc0 [kvm]
   kvm_arch_vcpu_ioctl_run+0x40b/0x670 [kvm]
   kvm_vcpu_ioctl+0x370/0x680 [kvm]
   ksys_ioctl+0x235/0x850
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x77/0x780
   entry_syscall_64_after_hwframe+0x49/0xbe
Signed-off-by: NWanpeng Li <wanpengli@tencent.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Commit 13db7734 ("KVM: x86: don't notify userspace IOAPIC on edge
EOI") said, edge-triggered interrupts don't set a bit in TMR, which means
that IOAPIC isn't notified on EOI. And var level indicates level-triggered
interrupt.
But commit 3159d36a ("KVM: x86: use generic function for MSI parsing")
replace var level with irq.level by mistake. Fix it by changing irq.level
to irq.trig_mode.

Cc: stable@vger.kernel.org
Fixes: 3159d36a ("KVM: x86: use generic function for MSI parsing")
Signed-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/emulate.c: In function 'x86_emulate_insn':
arch/x86/kvm/emulate.c:5686:22: error: cast between incompatible
function types from 'int (*)(struct x86_emulate_ctxt *)' to 'void
(*)(struct fastop *)' [-Werror=cast-function-type]
    rc = fastop(ctxt, (fastop_t)ctxt->execute);

Fix it by using an unnamed union of a (*execute) function pointer and a
(*fastop) function pointer.

Fixes: 3009afc6 ("KVM: x86: Use a typedef for fastop functions")
Suggested-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NQian Cai <cai@lca.pw>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The "u" field in the event has three states, -1/0/1.  Using u8 however means that
comparison with -1 will always fail, so change to signed char.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Fix wrong variable names and grammar error in comment.
Signed-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Reported with "make W=1" due to -Wmissing-prototypes.
Reported-by: NQian Cai <cai@lca.pw>
Reviewed-by: NMiaohe Lin <linmiaohe@huawei.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Avoid more embarrassing mistakes.  At least those that the compiler
can catch.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Due to some merge conflict, this file ended being alone under
Documentation/virtual.

The file itself is almost at ReST format. Just minor
adjustments are needed:

- Adjust title markup;
- Adjust a list identation;
- add a literal block markup;
- Add some blank lines.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This file is already in ReST compatible format.
So, rename it and add to the kvm's index.rst.

While here, use the standard conversion for document titles.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use document title and chapter markups;
- Add markups for literal blocks;
- Add markups for tables;
- use :field: for field descriptions;
- Add blank lines and adjust indentation.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This file is almost in ReST format. Just one change was
needed:

    - Add markups for a literal block and change its indentation.

While here, use the standard markup for the document title.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use document title and chapter markups;
- Add markups for tables;
- Use list markups;
- Add markups for literal blocks;
- Add blank lines.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This file is almost in ReST format. Just a small set of
changes were needed:

    - Add markups for lists;
    - Add markups for a literal block;
    - Adjust whitespaces.

While here, use the standard markup for the document title.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use document title and chapter markups;
- Add markups for tables;
- Add markups for literal blocks;
- Add blank lines and adjust indentation.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use document title and chapter markups;
- Add markups for literal blocks;
- use :field: for field descriptions;
- Add blank lines and adjust indentation.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use document title and chapter markups;
- Convert tables;
- Add markups for literal blocks;
- use :field: for field descriptions;
- Add blank lines and adjust indentation
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Add a title for the document;
- Adjust whitespaces for it to be properly formatted after
  parsed.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Add proper markups for titles;
- Adjust whitespaces and blank lines to match ReST
  needs;
- Mark literal blocks as such.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

convert api.txt document to ReST format while trying to keep
its format as close as possible with the authors intent, and
avoid adding uneeded markups.

- Use document title and chapter markups;
- Convert tables;
- Add markups for literal blocks;
- use :field: for field descriptions;
- Add blank lines and adjust indentation
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use title markups;
- adjust indentation and add blank lines as needed;
- adjust tables to match ReST accepted formats;
- mark code blocks as such.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use title markups;
- adjust indentation and add blank lines as needed;
- adjust tables to match ReST accepted formats;
- use :field: markups.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use title markups;
- adjust indentation and add blank lines as needed;
- use :field: markups;
- Use cross-references;
- mark code blocks as such.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use standard title markup;
- adjust lists;
- mark code blocks as such.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use title markups;
- adjust indentation and add blank lines as needed;
- adjust tables to match ReST accepted formats;
- use :field: markups;
- mark code blocks as such.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use standard markup for document title;
- Adjust indentation and add blank lines as needed;
- use the notes markup;
- mark code blocks as such.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This document is almost in ReST format. The only thing
needed is to mark a list as such and to add an extra
whitespace.

Yet, let's also use the standard document title markup,
as it makes easier if anyone wants later to add sessions
to it.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use title markups;
- change indent to match ReST syntax;
- use proper table markups;
- use literal block markups.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use title markups;
- change indent to match ReST syntax;
- use proper table markups;
- use literal block markups.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Fix document title to match ReST format
- Convert the table to be properly recognized
- use proper markups for literal blocks
- Some indentation fixes to match ReST

While here, add an index for kvm devices.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Use document title markup;
- Convert tables;
- Add blank lines and adjust indentation.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

- Fix document title to match ReST format
- Convert the table to be properly recognized
- Some indentation fixes to match ReST syntax.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Several URLs are pointing to outdated places.

Update the references for the URLs whose contents still exists,
removing the others.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Instead of pointing for a pre-2.4 and a seaparate patch,
update it to match current upstream, as UML was merged
a long time ago.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Despite being an old document, it contains lots of information
that could still be useful.

The document has a nice style with makes easy to convert to
ReST. So, let's convert it to ReST.

This patch does:

	- Use proper markups for titles;
	- Mark and proper indent literal blocks;
	- don't use an 'o' character for lists;
	- other minor changes required for the doc to be parsed.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Add this file to a new kvm/arm index.rst, in order for it to
be shown as part of the virt book.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The check cpu->hv_clock.system_time < 0 is redundant since system_time
is a u64 and hence can never be less than zero.  But what was actually
meant is to check that the result is positive, since kernel_ns and
v->kvm->arch.kvmclock_offset are both s64.
Reported-by: NColin King <colin.king@canonical.com>
Suggested-by: NSean Christopherson <sean.j.christopherson@intel.com>
Addresses-Coverity: ("Macro compares unsigned to 0")
Reviewed-by: NMiaohe Lin <linmiaohe@huawei.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

x86_register enum is not used, let's remove it.
Signed-off-by: NEric Auger <eric.auger@redhat.com>
Suggested-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Define PT_MAX_FULL_LEVELS as PT64_ROOT_MAX_LEVEL, i.e. 5, to fix shadow
paging for 5-level guest page tables.  PT_MAX_FULL_LEVELS is used to
size the arrays that track guest pages table information, i.e. using a
"max levels" of 4 causes KVM to access garbage beyond the end of an
array when querying state for level 5 entries.  E.g. FNAME(gpte_changed)
will read garbage and most likely return %true for a level 5 entry,
soft-hanging the guest because FNAME(fetch) will restart the guest
instead of creating SPTEs because it thinks the guest PTE has changed.

Note, KVM doesn't yet support 5-level nested EPT, so PT_MAX_FULL_LEVELS
gets to stay "4" for the PTTYPE_EPT case.

Fixes: 855feb67 ("KVM: MMU: Add 5 level EPT & Shadow page table support.")
Cc: stable@vger.kernel.org
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Hardcode the EPT page-walk level for L2 to be 4 levels, as KVM's MMU
currently also hardcodes the page walk level for nested EPT to be 4
levels.  The L2 guest is all but guaranteed to soft hang on its first
instruction when L1 is using EPT, as KVM will construct 4-level page
tables and then tell hardware to use 5-level page tables.

Fixes: 855feb67 ("KVM: MMU: Add 5 level EPT & Shadow page table support.")
Cc: stable@vger.kernel.org
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Fix some typos in the comments. Also fix coding style.
[Sean Christopherson rewrites the comment of write_fault_to_shadow_pgtable
field in struct kvm_vcpu_arch.]
Signed-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>