The kvm_exit tracepoint strangely always reported exits as being IRQs.
This seems to be because either the __print_symbolic or the tracepoint
macros use a variable named idx.

Take this chance to update the fields in the tracepoint to reflect the
concepts in the arm64 architecture that we pass to the tracepoint and
move the exception type table to the same location and header files as
the exits code.

We also clear out the exception code to 0 for IRQ exits (which
translates to UNKNOWN in text) to make it slighyly less confusing to
parse the trace output.

Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

When checking if there are any pending IRQs for the VM, consider the
active state and priority of the IRQs as well.

Otherwise we could be continuously scheduling a guest hypervisor without
it seeing an IRQ.

Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

When using the nospec API, it should be taken into account that:

"...if the CPU speculates past the bounds check then
 * array_index_nospec() will clamp the index within the range of [0,
 * size)."

The above is part of the header for macro array_index_nospec() in
linux/nospec.h

Now, in this particular case, if intid evaluates to exactly VGIC_MAX_SPI
or to exaclty VGIC_MAX_PRIVATE, the array_index_nospec() macro ends up
returning VGIC_MAX_SPI - 1 or VGIC_MAX_PRIVATE - 1 respectively, instead
of VGIC_MAX_SPI or VGIC_MAX_PRIVATE, which, based on the original logic:

	/* SGIs and PPIs */
	if (intid <= VGIC_MAX_PRIVATE)
 		return &vcpu->arch.vgic_cpu.private_irqs[intid];

 	/* SPIs */
	if (intid <= VGIC_MAX_SPI)
 		return &kvm->arch.vgic.spis[intid - VGIC_NR_PRIVATE_IRQS];

are valid values for intid.

Fix this by calling array_index_nospec() macro with VGIC_MAX_PRIVATE + 1
and VGIC_MAX_SPI + 1 as arguments for its parameter size.

Fixes: 41b87599 ("KVM: arm/arm64: vgic: fix possible spectre-v1 in vgic_get_irq()")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
[dropped the SPI part which was fixed separately]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

SPIs should be checked against the VMs specific configuration, and
not the architectural maximum.

Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

In attempting to re-construct the logic for our stage 2 page table
layout I found the reasoning in the comment explaining how we calculate
the number of levels used for stage 2 page tables a bit backwards.

This commit attempts to clarify the comment, to make it slightly easier
to read without having the Arm ARM open on the right page.

While we're at it, fixup a typo in a comment that was recently changed.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

To change the active state of an MMIO, halt is requested for all vcpus of
the affected guest before modifying the IRQ state. This is done by calling
cond_resched_lock() in vgic_mmio_change_active(). However interrupts are
disabled at this point and we cannot reschedule a vcpu.

We actually don't need any of this, as kvm_arm_halt_guest ensures that
all the other vcpus are out of the guest. Let's just drop that useless
code.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Suggested-by: Christoffer Dall <christoffer.dall@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

KVM only supports PMD hugepages at stage 2. Now that the various page
handling routines are updated, extend the stage 2 fault handling to
map in PUD hugepages.

Addition of PUD hugepage support enables additional page sizes (e.g.,
1G with 4K granule) which can be useful on cores that support mapping
larger block sizes in the TLB entries.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
[ Replace BUG() => WARN_ON(1) for arm32 PUD helpers ]
Signed-off-by: Suzuki Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

In preparation for creating larger hugepages at Stage 2, add support
to the age handling notifiers for PUD hugepages when encountered.

Provide trivial helpers for arm32 to allow sharing code.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
[ Replaced BUG() => WARN_ON(1) for arm32 PUD helpers ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

In preparation for creating larger hugepages at Stage 2, extend the
access fault handling at Stage 2 to support PUD hugepages when
encountered.

Provide trivial helpers for arm32 to allow sharing of code.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
[ Replaced BUG() => WARN_ON(1) in PUD helpers ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

In preparation for creating PUD hugepages at stage 2, add support for
detecting execute permissions on PUD page table entries. Faults due to
lack of execute permissions on page table entries is used to perform
i-cache invalidation on first execute.

Provide trivial implementations of arm32 helpers to allow sharing of
code.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
[ Replaced BUG() => WARN_ON(1) in arm32 PUD helpers ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

In preparation for creating PUD hugepages at stage 2, add support for
write protecting PUD hugepages when they are encountered. Write
protecting guest tables is used to track dirty pages when migrating
VMs.

Also, provide trivial implementations of required kvm_s2pud_* helpers
to allow sharing of code with arm32.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
[ Replaced BUG() => WARN_ON() in arm32 pud helpers ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Introduce helpers to abstract architectural handling of the conversion
of pfn to page table entries and marking a PMD page table entry as a
block entry.

The helpers are introduced in preparation for supporting PUD hugepages
at stage 2 - which are supported on arm64 but do not exist on arm.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Stage 2 fault handler marks a page as executable if it is handling an
execution fault or if it was a permission fault in which case the
executable bit needs to be preserved.

The logic to decide if the page should be marked executable is
duplicated for PMD and PTE entries. To avoid creating another copy
when support for PUD hugepages is introduced refactor the code to
share the checks needed to mark a page table entry as executable.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

The code for operations such as marking the pfn as dirty, and
dcache/icache maintenance during stage 2 fault handling is duplicated
between normal pages and PMD hugepages.

Instead of creating another copy of the operations when we introduce
PUD hugepages, let's share them across the different pagesizes.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

When restoring the active state from userspace, we don't know which CPU
was the source for the active state, and this is not architecturally
exposed in any of the register state.

Set the active_source to 0 in this case.  In the future, we can expand
on this and exposse the information as additional information to
userspace for GICv2 if anyone cares.

Cc: stable@vger.kernel.org
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

We recently addressed a VMID generation race by introducing a read/write
lock around accesses and updates to the vmid generation values.

However, kvm_arch_vcpu_ioctl_run() also calls need_new_vmid_gen() but
does so without taking the read lock.

As far as I can tell, this can lead to the same kind of race:

  VM 0, VCPU 0			VM 0, VCPU 1
  ------------			------------
  update_vttbr (vmid 254)
  				update_vttbr (vmid 1) // roll over
				read_lock(kvm_vmid_lock);
				force_vm_exit()
  local_irq_disable
  need_new_vmid_gen == false //because vmid gen matches

  enter_guest (vmid 254)
  				kvm_arch.vttbr = <PGD>:<VMID 1>
				read_unlock(kvm_vmid_lock);

  				enter_guest (vmid 1)

Which results in running two VCPUs in the same VM with different VMIDs
and (even worse) other VCPUs from other VMs could now allocate clashing
VMID 254 from the new generation as long as VCPU 0 is not exiting.

Attempt to solve this by making sure vttbr is updated before another CPU
can observe the updated VMID generation.

Cc: stable@vger.kernel.org
Fixes: f0cf47d9 "KVM: arm/arm64: Close VMID generation race"
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

When we emulate a guest instruction, we don't advance the hardware
singlestep state machine, and thus the guest will receive a software
step exception after a next instruction which is not emulated by the
host.

We bodge around this in an ad-hoc fashion. Sometimes we explicitly check
whether userspace requested a single step, and fake a debug exception
from within the kernel. Other times, we advance the HW singlestep state
rely on the HW to generate the exception for us. Thus, the observed step
behaviour differs for host and guest.

Let's make this simpler and consistent by always advancing the HW
singlestep state machine when we skip an instruction. Thus we can rely
on the hardware to generate the singlestep exception for us, and never
need to explicitly check for an active-pending step, nor do we need to
fake a debug exception from the guest.

Cc: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

When we emulate an MMIO instruction, we advance the CPU state within
decode_hsr(), before emulating the instruction effects.

Having this logic in decode_hsr() is opaque, and advancing the state
before emulation is problematic. It gets in the way of applying
consistent single-step logic, and it prevents us from being able to fail
an MMIO instruction with a synchronous exception.

Clean this up by only advancing the CPU state *after* the effects of the
instruction are emulated.

Cc: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Revert 5ff7091f ("mm, mmu_notifier: annotate mmu notifiers with
blockable invalidate callbacks").

MMU_INVALIDATE_DOES_NOT_BLOCK flags was the only one used and it is no
longer needed since 93065ac7 ("mm, oom: distinguish blockable mode for
mmu notifiers").  We now have a full support for per range !blocking
behavior so we can drop the stop gap workaround which the per notifier
flag was used for.

Link: http://lkml.kernel.org/r/20180827112623.8992-4-mhocko@kernel.org


Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The commit 539aee0e ("KVM: arm64: Share the parts of
get/set events useful to 32bit") shares the get/set events
helper for arm64 and arm32, but forgot to share the cap
extension code.

User space will check whether KVM supports vcpu events by
checking the KVM_CAP_VCPU_EVENTS extension

Acked-by: James Morse <james.morse@arm.com>
Reviewed-by : Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Dongjiu Geng <gengdongjiu@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Rename kvm_arch_dev_ioctl_check_extension() to
kvm_arch_vm_ioctl_check_extension(), because it does
not have any relationship with device.

Renaming this function can make code readable.

Cc: James Morse <james.morse@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Dongjiu Geng <gengdongjiu@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

At boot time, KVM stashes the host MDCR_EL2 value, but only does this
when the kernel is not running in hyp mode (i.e. is non-VHE). In these
cases, the stashed value of MDCR_EL2.HPMN happens to be zero, which can
lead to CONSTRAINED UNPREDICTABLE behaviour.

Since we use this value to derive the MDCR_EL2 value when switching
to/from a guest, after a guest have been run, the performance counters
do not behave as expected. This has been observed to result in accesses
via PMXEVTYPER_EL0 and PMXEVCNTR_EL0 not affecting the relevant
counters, resulting in events not being counted. In these cases, only
the fixed-purpose cycle counter appears to work as expected.

Fix this by always stashing the host MDCR_EL2 value, regardless of VHE.

Cc: Christopher Dall <christoffer.dall@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Fixes: 1e947bad ("arm64: KVM: Skip HYP setup when already running in HYP")
Tested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

The original comment is little hard to understand.

No functional change, just amend the comment a little.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Coalesced pio is based on coalesced mmio and can be used for some port
like rtc port, pci-host config port and so on.

Specially in case of rtc as coalesced pio, some versions of windows guest
access rtc frequently because of rtc as system tick. guest access rtc like
this: write register index to 0x70, then write or read data from 0x71.
writing 0x70 port is just as index and do nothing else. So we can use
coalesced pio to handle this scene to reduce VM-EXIT time.

When starting and closing a virtual machine, it will access pci-host config
port frequently. So setting these port as coalesced pio can reduce startup
and shutdown time.

without my patch, get the vm-exit time of accessing rtc 0x70 and piix 0xcf8
using perf tools: (guest OS : windows 7 64bit)
IO Port Access  Samples Samples%  Time%  Min Time  Max Time  Avg time
0x70:POUT        86     30.99%    74.59%   9us      29us    10.75us (+- 3.41%)
0xcf8:POUT     1119     2.60%     2.12%   2.79us    56.83us 3.41us (+- 2.23%)

with my patch
IO Port Access  Samples Samples%  Time%   Min Time  Max Time   Avg time
0x70:POUT       106    32.02%    29.47%    0us      10us     1.57us (+- 7.38%)
0xcf8:POUT      1065    1.67%     0.28%   0.41us    65.44us   0.66us (+- 10.55%)

Signed-off-by: Peng Hao <peng.hao2@zte.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

update_memslots() is only called by __kvm_set_memory_region(), in which
"change" is calculated and indicates how to adjust slots->used_slots

  * increase by one if it is KVM_MR_CREATE
  * decrease by one if it is KVM_MR_DELETE
  * not change for others

This patch adjusts slots->used_slots in update_memslots() based on "change"
value instead of re-calculate those states again.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

We can use 'NULL' to represent 'all cpus' case in
kvm_make_vcpus_request_mask() and avoid building vCPU mask with
all vCPUs.

Suggested-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

PageTransCompoundMap() returns true for hugetlbfs and THP
hugepages. This behaviour incorrectly leads to stage 2 faults for
unsupported hugepage sizes (e.g., 64K hugepage with 4K pages) to be
treated as THP faults.

Tighten the check to filter out hugetlbfs pages. This also leads to
consistently mapping all unsupported hugepage sizes as PTE level
entries at stage 2.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Suzuki Poulose <suzuki.poulose@arm.com>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: stable@vger.kernel.org # v4.13+
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

__cpu_init_stage2 doesn't do anything anymore on arm64, and is
totally non-sensical if running VHE (as VHE is 64bit only).

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

VM tends to be a very overloaded term in KVM, so let's keep it
to describe the virtual machine. For the virtual memory setup,
let's use the "stage2" suffix.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

So far we have restricted the IPA size of the VM to the default
value (40bits). Now that we can manage the IPA size per VM and
support dynamic stage2 page tables, we can allow VMs to have
larger IPA. This patch introduces a the maximum IPA size
supported on the host. This is decided by the following factors :

 1) Maximum PARange supported by the CPUs - This can be inferred
    from the system wide safe value.
 2) Maximum PA size supported by the host kernel (48 vs 52)
 3) Number of levels in the host page table (as we base our
    stage2 tables on the host table helpers).

Since the stage2 page table code is dependent on the stage1
page table, we always ensure that :

  Number of Levels at Stage1 >= Number of Levels at Stage2

So we limit the IPA to make sure that the above condition
is satisfied. This will affect the following combinations
of VA_BITS and IPA for different page sizes.

  Host configuration | Unsupported IPA ranges
  39bit VA, 4K       | [44, 48]
  36bit VA, 16K      | [41, 48]
  42bit VA, 64K      | [47, 52]

Supporting the above combinations need independent stage2
page table manipulation code, which would need substantial
changes. We could purse the solution independently and
switch the page table code once we have it ready.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <cdall@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Add support for handling 52bit guest physical address to the
VGIC layer. So far we have limited the guest physical address
to 48bits, by explicitly masking the upper bits. This patch
removes the restriction. We do not have to check if the host
supports 52bit as the gpa is always validated during an access.
(e.g, kvm_{read/write}_guest, kvm_is_visible_gfn()).
Also, the ITS table save-restore is also not affected with
the enhancement. The DTE entries already store the bits[51:8]
of the ITT_addr (with a 256byte alignment).

Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <cdall@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
[ Macro clean ups, fix PROPBASER and PENDBASER accesses ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Right now the stage2 page table for a VM is hard coded, assuming
an IPA of 40bits. As we are about to add support for per VM IPA,
prepare the stage2 page table helpers to accept the kvm instance
to make the right decision for the VM. No functional changes.
Adds stage2_pgd_size(kvm) to replace S2_PGD_SIZE. Also, moves
some of the definitions in arm32 to align with the arm64.
Also drop the _AC() specifier constants wherever possible.

Cc: Christoffer Dall <cdall@kernel.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Allow the arch backends to perform VM specific initialisation.
This will be later used to handle IPA size configuration and per-VM
VTCR configuration on arm64.

Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <cdall@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

On a 4-level page table pgd entry can be empty, unlike a 3-level
page table. Remove the spurious WARN_ON() in stage_get_pud().

Acked-by: Christoffer Dall <cdall@kernel.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

So far we have only supported 3 level page table with fixed IPA of
40bits, where PUD is folded. With 4 level page tables, we need
to check if the PUD entry is valid or not. Fix stage2_flush_memslot()
to do this check, before walking down the table.

Acked-by: Christoffer Dall <cdall@kernel.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

This simplifies the code making it clearer what is going on, and
making the siginfo generation easier to maintain.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

We rely on cpufeature framework to detect and enable CNP so for KVM we
need to patch hyp to set CNP bit just before TTBR0_EL2 gets written.

For the guest we encode CNP bit while building vttbr, so we don't need
to bother with that in a world switch.

Reviewed-by: James Morse <james.morse@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

kvm_unmap_hva is long gone, and we only have kvm_unmap_hva_range to
deal with. Drop the now obsolete code.

Fixes: fb1522e0 ("KVM: update to new mmu_notifier semantic v2")
Cc: James Hogan <jhogan@kernel.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>

When triggering a CoW, we unmap the RO page via an MMU notifier
(invalidate_range_start), and then populate the new PTE using another
one (change_pte). In the meantime, we'll have copied the old page
into the new one.

The problem is that the data for the new page is sitting in the
cache, and should the guest have an uncached mapping to that page
(or its MMU off), following accesses will bypass the cache.

In a way, this is similar to what happens on a translation fault:
We need to clean the page to the PoC before mapping it. So let's just
do that.

This fixes a KVM unit test regression observed on a HiSilicon platform,
and subsequently reproduced on Seattle.

Fixes: a9c0e12e ("KVM: arm/arm64: Only clean the dcache on translation fault")
Cc: stable@vger.kernel.org # v4.16+
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>

There are several blockable mmu notifiers which might sleep in
mmu_notifier_invalidate_range_start and that is a problem for the
oom_reaper because it needs to guarantee a forward progress so it cannot
depend on any sleepable locks.

Currently we simply back off and mark an oom victim with blockable mmu
notifiers as done after a short sleep.  That can result in selecting a new
oom victim prematurely because the previous one still hasn't torn its
memory down yet.

We can do much better though.  Even if mmu notifiers use sleepable locks
there is no reason to automatically assume those locks are held.  Moreover
majority of notifiers only care about a portion of the address space and
there is absolutely zero reason to fail when we are unmapping an unrelated
range.  Many notifiers do really block and wait for HW which is harder to
handle and we have to bail out though.

This patch handles the low hanging fruit.
__mmu_notifier_invalidate_range_start gets a blockable flag and callbacks
are not allowed to sleep if the flag is set to false.  This is achieved by
using trylock instead of the sleepable lock for most callbacks and
continue as long as we do not block down the call chain.

I think we can improve that even further because there is a common pattern
to do a range lookup first and then do something about that.  The first
part can be done without a sleeping lock in most cases AFAICS.

The oom_reaper end then simply retries if there is at least one notifier
which couldn't make any progress in !blockable mode.  A retry loop is
already implemented to wait for the mmap_sem and this is basically the
same thing.

The simplest way for driver developers to test this code path is to wrap
userspace code which uses these notifiers into a memcg and set the hard
limit to hit the oom.  This can be done e.g.  after the test faults in all
the mmu notifier managed memory and set the hard limit to something really
small.  Then we are looking for a proper process tear down.

[akpm@linux-foundation.org: coding style fixes]
[akpm@linux-foundation.org: minor code simplification]
Link: http://lkml.kernel.org/r/20180716115058.5559-1-mhocko@kernel.org


Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Christian König <christian.koenig@amd.com> # AMD notifiers
Acked-by: Leon Romanovsky <leonro@mellanox.com> # mlx and umem_odp
Reported-by: David Rientjes <rientjes@google.com>
Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Mike Marciniszyn <mike.marciniszyn@intel.com>
Cc: Dennis Dalessandro <dennis.dalessandro@intel.com>
Cc: Sudeep Dutt <sudeep.dutt@intel.com>
Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>