Renaming docs seems to be en vogue at the moment, so fix on of the
grossly misnamed directories.  We usually never use "virtual" as
a shortcut for virtualization in the kernel, but always virt,
as seen in the virt/ top-level directory.  Fix up the documentation
to match that.

Fixes: ed16648eb5b8 ("Move kvm, uml, and lguest subdirectories under a common "virtual" directory, I.E:")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Inspired by commit 9cac38dd5d (KVM/s390: Set preempted flag during
vcpu wakeup and interrupt delivery), we want to also boost not just
lock holders but also vCPUs that are delivering interrupts. Most
smp_call_function_many calls are synchronous, so the IPI target vCPUs
are also good yield candidates.  This patch introduces vcpu->ready to
boost vCPUs during wakeup and interrupt delivery time; unlike s390 we do
not reuse vcpu->preempted so that voluntarily preempted vCPUs are taken
into account by kvm_vcpu_on_spin, but vmx_vcpu_pi_put is not affected
(VT-d PI handles voluntary preemption separately, in pi_pre_block).

Testing on 80 HT 2 socket Xeon Skylake server, with 80 vCPUs VM 80GB RAM:
ebizzy -M

            vanilla     boosting    improved
1VM          21443       23520         9%
2VM           2800        8000       180%
3VM           1800        3100        72%

Testing on my Haswell desktop 8 HT, with 8 vCPUs VM 8GB RAM, two VMs,
one running ebizzy -M, the other running 'stress --cpu 2':

w/ boosting + w/o pv sched yield(vanilla)

            vanilla     boosting   improved
              1570         4000      155%

w/ boosting + w/ pv sched yield(vanilla)

            vanilla     boosting   improved
              1844         5157      179%

w/o boosting, perf top in VM:

 72.33%  [kernel]       [k] smp_call_function_many
  4.22%  [kernel]       [k] call_function_i
  3.71%  [kernel]       [k] async_page_fault

w/ boosting, perf top in VM:

 38.43%  [kernel]       [k] smp_call_function_many
  6.31%  [kernel]       [k] async_page_fault
  6.13%  libc-2.23.so   [.] __memcpy_avx_unaligned
  4.88%  [kernel]       [k] call_function_interrupt

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Pull KVM updates from Paolo Bonzini:
 "ARM:
   - support for chained PMU counters in guests
   - improved SError handling
   - handle Neoverse N1 erratum #1349291
   - allow side-channel mitigation status to be migrated
   - standardise most AArch64 system register accesses to msr_s/mrs_s
   - fix host MPIDR corruption on 32bit
   - selftests ckleanups

  x86:
   - PMU event {white,black}listing
   - ability for the guest to disable host-side interrupt polling
   - fixes for enlightened VMCS (Hyper-V pv nested virtualization),
   - new hypercall to yield to IPI target
   - support for passing cstate MSRs through to the guest
   - lots of cleanups and optimizations

  Generic:
   - Some txt->rST conversions for the documentation"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (128 commits)
  Documentation: virtual: Add toctree hooks
  Documentation: kvm: Convert cpuid.txt to .rst
  Documentation: virtual: Convert paravirt_ops.txt to .rst
  KVM: x86: Unconditionally enable irqs in guest context
  KVM: x86: PMU Event Filter
  kvm: x86: Fix -Wmissing-prototypes warnings
  KVM: Properly check if "page" is valid in kvm_vcpu_unmap
  KVM: arm/arm64: Initialise host's MPIDRs by reading the actual register
  KVM: LAPIC: Retry tune per-vCPU timer_advance_ns if adaptive tuning goes insane
  kvm: LAPIC: write down valid APIC registers
  KVM: arm64: Migrate _elx sysreg accessors to msr_s/mrs_s
  KVM: doc: Add API documentation on the KVM_REG_ARM_WORKAROUNDS register
  KVM: arm/arm64: Add save/restore support for firmware workaround state
  arm64: KVM: Propagate full Spectre v2 workaround state to KVM guests
  KVM: arm/arm64: Support chained PMU counters
  KVM: arm/arm64: Remove pmc->bitmask
  KVM: arm/arm64: Re-create event when setting counter value
  KVM: arm/arm64: Extract duplicated code to own function
  KVM: arm/arm64: Rename kvm_pmu_{enable/disable}_counter functions
  KVM: LAPIC: ARBPRI is a reserved register for x2APIC
  ...

The PTE allocations in arm64 are identical to the generic ones modulo the
GFP flags.

Using the generic pte_alloc_one() functions ensures that the user page
tables are allocated with __GFP_ACCOUNT set.

The arm64 definition of PGALLOC_GFP is removed and replaced with
GFP_PGTABLE_USER for p[gum]d_alloc_one() for the user page tables and
GFP_PGTABLE_KERNEL for the kernel page tables. The KVM memory cache is now
using GFP_PGTABLE_USER.

The mappings created with create_pgd_mapping() are now using
GFP_PGTABLE_KERNEL.

The conversion to the generic version of pte_free_kernel() removes the NULL
check for pte.

The pte_free() version on arm64 is identical to the generic one and
can be simply dropped.

[cai@lca.pw: fix a bogus GFP flag in pgd_alloc()]
  Link: https://lore.kernel.org/r/1559656836-24940-1-git-send-email-cai@lca.pw/
[and fix it more]
  Link: https://lore.kernel.org/linux-mm/20190617151252.GF16810@rapoport-lnx/
Link: http://lkml.kernel.org/r/1557296232-15361-5-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Guo Ren <ren_guo@c-sky.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Creasey <sammy@sammy.net>
Cc: Vincent Chen <deanbo422@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

KVM/arm updates for 5.3

- Add support for chained PMU counters in guests
- Improve SError handling
- Handle Neoverse N1 erratum #1349291
- Allow side-channel mitigation status to be migrated
- Standardise most AArch64 system register accesses to msr_s/mrs_s
- Fix host MPIDR corruption on 32bit

The field "page" is initialized to KVM_UNMAPPED_PAGE when it is not used
(i.e. when the memory lives outside kernel control). So this check will
always end up using kunmap even for memremap regions.

Fixes: e45adf665a53 ("KVM: Introduce a new guest mapping API")
Cc: stable@vger.kernel.org
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

As part of setting up the host context, we populate its
MPIDR by using cpu_logical_map(). It turns out that contrary
to arm64, cpu_logical_map() on 32bit ARM doesn't return the
*full* MPIDR, but a truncated version.

This leaves the host MPIDR slightly corrupted after the first
run of a VM, since we won't correctly restore the MPIDR on
exit. Oops.

Since we cannot trust cpu_logical_map(), let's adopt a different
strategy. We move the initialization of the host CPU context as
part of the per-CPU initialization (which, in retrospect, makes
a lot of sense), and directly read the MPIDR from the HW. This
is guaranteed to work on both arm and arm64.

Reported-by: Andre Przywara <Andre.Przywara@arm.com>
Tested-by: Andre Przywara <Andre.Przywara@arm.com>
Fixes: 32f139551954 ("arm/arm64: KVM: Statically configure the host's view of MPIDR")
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Currently, the {read,write}_sysreg_el*() accessors for accessing
particular ELs' sysregs in the presence of VHE rely on some local
hacks and define their system register encodings in a way that is
inconsistent with the core definitions in <asm/sysreg.h>.

As a result, it is necessary to add duplicate definitions for any
system register that already needs a definition in sysreg.h for
other reasons.

This is a bit of a maintenance headache, and the reasons for the
_el*() accessors working the way they do is a bit historical.

This patch gets rid of the shadow sysreg definitions in
<asm/kvm_hyp.h>, converts the _el*() accessors to use the core
__msr_s/__mrs_s interface, and converts all call sites to use the
standard sysreg #define names (i.e., upper case, with SYS_ prefix).

This patch will conflict heavily anyway, so the opportunity
to clean up some bad whitespace in the context of the changes is
taken.

The change exposes a few system registers that have no sysreg.h
definition, due to msr_s/mrs_s being used in place of msr/mrs:
additions are made in order to fill in the gaps.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Link: https://www.spinics.net/lists/kvm-arm/msg31717.html
[Rebased to v4.21-rc1]
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
[Rebased to v5.2-rc5, changelog updates]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

KVM implements the firmware interface for mitigating cache speculation
vulnerabilities. Guests may use this interface to ensure mitigation is
active.
If we want to migrate such a guest to a host with a different support
level for those workarounds, migration might need to fail, to ensure that
critical guests don't loose their protection.

Introduce a way for userland to save and restore the workarounds state.
On restoring we do checks that make sure we don't downgrade our
mitigation level.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Recent commits added the explicit notion of "workaround not required" to
the state of the Spectre v2 (aka. BP_HARDENING) workaround, where we
just had "needed" and "unknown" before.

Export this knowledge to the rest of the kernel and enhance the existing
kvm_arm_harden_branch_predictor() to report this new state as well.
Export this new state to guests when they use KVM's firmware interface
emulation.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>