Commit Graph

336 Commits

Author SHA1 Message Date
Dan Williams
ba049e93ae kvm: rename pfn_t to kvm_pfn_t
To date, we have implemented two I/O usage models for persistent memory,
PMEM (a persistent "ram disk") and DAX (mmap persistent memory into
userspace).  This series adds a third, DAX-GUP, that allows DAX mappings
to be the target of direct-i/o.  It allows userspace to coordinate
DMA/RDMA from/to persistent memory.

The implementation leverages the ZONE_DEVICE mm-zone that went into
4.3-rc1 (also discussed at kernel summit) to flag pages that are owned
and dynamically mapped by a device driver.  The pmem driver, after
mapping a persistent memory range into the system memmap via
devm_memremap_pages(), arranges for DAX to distinguish pfn-only versus
page-backed pmem-pfns via flags in the new pfn_t type.

The DAX code, upon seeing a PFN_DEV+PFN_MAP flagged pfn, flags the
resulting pte(s) inserted into the process page tables with a new
_PAGE_DEVMAP flag.  Later, when get_user_pages() is walking ptes it keys
off _PAGE_DEVMAP to pin the device hosting the page range active.
Finally, get_page() and put_page() are modified to take references
against the device driver established page mapping.

Finally, this need for "struct page" for persistent memory requires
memory capacity to store the memmap array.  Given the memmap array for a
large pool of persistent may exhaust available DRAM introduce a
mechanism to allocate the memmap from persistent memory.  The new
"struct vmem_altmap *" parameter to devm_memremap_pages() enables
arch_add_memory() to use reserved pmem capacity rather than the page
allocator.

This patch (of 18):

The core has developed a need for a "pfn_t" type [1].  Move the existing
pfn_t in KVM to kvm_pfn_t [2].

[1]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002199.html
[2]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002218.html

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 17:56:32 -08:00
Pavel Fedin
c7da6fa43c arm/arm64: KVM: Detect vGIC presence at runtime
Before commit 662d971584
("arm/arm64: KVM: Kill CONFIG_KVM_ARM_{VGIC,TIMER}") is was possible to
compile the kernel without vGIC and vTimer support. Commit message says
about possibility to detect vGIC support in runtime, but this has never
been implemented.

This patch introduces runtime check, restoring the lost functionality.
It again allows to use KVM on hardware without vGIC. Interrupt
controller has to be emulated in userspace in this case.

-ENODEV return code from probe function means there's no GIC at all.
-ENXIO happens when, for example, there is GIC node in the device tree,
but it does not specify vGIC resources. Any other error code is still
treated as full stop because it might mean some really serious problems.

Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-18 12:01:58 +00:00
Vladimir Murzin
20475f784d arm64: KVM: Add support for 16-bit VMID
The ARMv8.1 architecture extension allows to choose between 8-bit and
16-bit of VMID, so use this capability for KVM.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-18 10:15:12 +00:00
Vladimir Murzin
9d4dc68834 arm/arm64: KVM: Remove unreferenced S2_PGD_ORDER
Since commit a987370 ("arm64: KVM: Fix stage-2 PGD allocation to have
per-page refcounting") there is no reference to S2_PGD_ORDER, so kill it
for the good.

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-18 10:15:11 +00:00
Marc Zyngier
e078ef8151 ARM: KVM: Cleanup exception injection
David Binderman reported that the exception injection code had a
couple of unused variables lingering around.

Upon examination, it looked like this code could do with an
anticipated spring cleaning, which amounts to deduplicating
the CPSR/SPSR update, and making it look a bit more like
the architecture spec.

The spurious variables are removed in the process.

Reported-by: David Binderman <dcb314@hotmail.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-18 10:14:54 +00:00
Marc Zyngier
910917bb7d arm64: KVM: Map the kernel RO section into HYP
In order to run C code in HYP, we must make sure that the kernel's
RO section is mapped into HYP (otherwise things break badly).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-12-14 11:30:43 +00:00
Amit Tomar
b19e6892a9 KVM: arm/arm64: Count guest exit due to various reasons
It would add guest exit statistics to debugfs, this can be helpful
while measuring KVM performance.

  [ Renamed some of the field names - Christoffer ]

Signed-off-by: Amit Singh Tomar <amittomer25@gmail.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-12-14 11:30:00 +00:00
Ard Biesheuvel
0de58f8528 ARM/arm64: KVM: correct PTE uncachedness check
Commit e6fab54423 ("ARM/arm64: KVM: test properly for a PTE's
uncachedness") modified the logic to test whether a HYP or stage-2
mapping needs flushing, from [incorrectly] interpreting the page table
attributes to [incorrectly] checking whether the PFN that backs the
mapping is covered by host system RAM. The PFN number is part of the
output of the translation, not the input, so we have to use pte_pfn()
on the contents of the PTE, not __phys_to_pfn() on the HYP virtual
address or stage-2 intermediate physical address.

Fixes: e6fab54423 ("ARM/arm64: KVM: test properly for a PTE's uncachedness")
Cc: stable@vger.kernel.org
Tested-by: Pavel Fedin <p.fedin@samsung.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-04 16:30:17 +00:00
Pavel Fedin
f6be563abb arm64: KVM: Get rid of old vcpu_reg()
Using oldstyle vcpu_reg() accessor is proven to be inappropriate and
unsafe on ARM64. This patch converts the rest of use cases to new
accessors and completely removes vcpu_reg() on ARM64.

Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-04 16:30:03 +00:00
Pavel Fedin
bc45a516fa arm64: KVM: Correctly handle zero register during MMIO
On ARM64 register index of 31 corresponds to both zero register and SP.
However, all memory access instructions, use ZR as transfer register. SP
is used only as a base register in indirect memory addressing, or by
register-register arithmetics, which cannot be trapped here.

Correct emulation is achieved by introducing new register accessor
functions, which can do special handling for reg_num == 31. These new
accessors intentionally do not rely on old vcpu_reg() on ARM64, because
it is to be removed. Since the affected code is shared by both ARM
flavours, implementations of these accessors are also added to ARM32 code.

This patch fixes setting MMIO register to a random value (actually SP)
instead of zero by something like:

 *((volatile int *)reg) = 0;

compilers tend to generate "str wzr, [xx]" here

[Marc: Fixed 32bit splat]

Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-04 16:29:37 +00:00
Christoffer Dall
7e16aa81f9 KVM: arm/arm64: Fix preemptible timer active state crazyness
We were setting the physical active state on the GIC distributor in a
preemptible section, which could cause us to set the active state on
different physical CPU from the one we were actually going to run on,
hacoc ensues.

Since we are no longer descheduling/scheduling soft timers in the
flush/sync timer functions, simply moving the timer flush into a
non-preemptible section.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-11-24 18:04:00 +01:00
Ard Biesheuvel
e6fab54423 ARM/arm64: KVM: test properly for a PTE's uncachedness
The open coded tests for checking whether a PTE maps a page as
uncached use a flawed '(pte_val(xxx) & CONST) != CONST' pattern,
which is not guaranteed to work since the type of a mapping is
not a set of mutually exclusive bits

For HYP mappings, the type is an index into the MAIR table (i.e, the
index itself does not contain any information whatsoever about the
type of the mapping), and for stage-2 mappings it is a bit field where
normal memory and device types are defined as follows:

    #define MT_S2_NORMAL            0xf
    #define MT_S2_DEVICE_nGnRE      0x1

I.e., masking *and* comparing with the latter matches on the former,
and we have been getting lucky merely because the S2 device mappings
also have the PTE_UXN bit set, or we would misidentify memory mappings
as device mappings.

Since the unmap_range() code path (which contains one instance of the
flawed test) is used both for HYP mappings and stage-2 mappings, and
considering the difference between the two, it is non-trivial to fix
this by rewriting the tests in place, as it would involve passing
down the type of mapping through all the functions.

However, since HYP mappings and stage-2 mappings both deal with host
physical addresses, we can simply check whether the mapping is backed
by memory that is managed by the host kernel, and only perform the
D-cache maintenance if this is the case.

Cc: stable@vger.kernel.org
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Pavel Fedin <p.fedin@samsung.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-11-24 17:58:00 +01:00
Christoffer Dall
b5905dc12e arm/arm64: KVM: Improve kvm_exit tracepoint
The ARM architecture only saves the exit class to the HSR (ESR_EL2 for
arm64) on synchronous exceptions, not on asynchronous exceptions like an
IRQ.  However, we only report the exception class on kvm_exit, which is
confusing because an IRQ looks like it exited at some PC with the same
reason as the previous exit.  Add a lookup table for the exception index
and prepend the kvm_exit tracepoint text with the exception type to
clarify this situation.

Also resolve the exception class (EC) to a human-friendly text version
so the trace output becomes immediately usable for debugging this code.

Cc: Wei Huang <wei@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22 23:01:47 +02:00
Eric Auger
3b92830ad4 KVM: arm/arm64: implement kvm_arm_[halt,resume]_guest
We introduce kvm_arm_halt_guest and resume functions. They
will be used for IRQ forward state change.

Halt is synchronous and prevents the guest from being re-entered.
We use the same mechanism put in place for PSCI former pause,
now renamed power_off. A new flag is introduced in arch vcpu state,
pause, only meant to be used by those functions.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22 23:01:46 +02:00
Eric Auger
101d3da09c KVM: arm/arm64: check power_off in critical section before VCPU run
In case a vcpu off PSCI call is called just after we executed the
vcpu_sleep check, we can enter the guest although power_off
is set. Let's check the power_off state in the critical section,
just before entering the guest.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Reported-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22 23:01:46 +02:00
Eric Auger
4f5f1dc036 KVM: arm/arm64: check power_off in kvm_arch_vcpu_runnable
kvm_arch_vcpu_runnable now also checks whether the power_off
flag is set.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22 23:01:46 +02:00
Eric Auger
3781528e30 KVM: arm/arm64: rename pause into power_off
The kvm_vcpu_arch pause field is renamed into power_off to prepare
for the introduction of a new pause field. Also vcpu_pause is renamed
into vcpu_sleep since we will sleep until both power_off and pause are
false.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22 23:01:45 +02:00
Wei Huang
75755c6d02 arm/arm64: KVM : Enable vhost device selection under KVM config menu
vhost drivers provide guest VMs with better I/O performance and lower
CPU utilization. This patch allows users to select vhost devices under
KVM configuration menu on ARM. This makes vhost support on arm/arm64
on a par with other architectures (e.g. x86, ppc).

Signed-off-by: Wei Huang <wei@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22 23:01:45 +02:00
Christoffer Dall
4b4b4512da arm/arm64: KVM: Rework the arch timer to use level-triggered semantics
The arch timer currently uses edge-triggered semantics in the sense that
the line is never sampled by the vgic and lowering the line from the
timer to the vgic doesn't have any effect on the pending state of
virtual interrupts in the vgic.  This means that we do not support a
guest with the otherwise valid behavior of (1) disable interrupts (2)
enable the timer (3) disable the timer (4) enable interrupts.  Such a
guest would validly not expect to see any interrupts on real hardware,
but will see interrupts on KVM.

This patch fixes this shortcoming through the following series of
changes.

First, we change the flow of the timer/vgic sync/flush operations.  Now
the timer is always flushed/synced before the vgic, because the vgic
samples the state of the timer output.  This has the implication that we
move the timer operations in to non-preempible sections, but that is
fine after the previous commit getting rid of hrtimer schedules on every
entry/exit.

Second, we change the internal behavior of the timer, letting the timer
keep track of its previous output state, and only lower/raise the line
to the vgic when the state changes.  Note that in theory this could have
been accomplished more simply by signalling the vgic every time the
state *potentially* changed, but we don't want to be hitting the vgic
more often than necessary.

Third, we get rid of the use of the map->active field in the vgic and
instead simply set the interrupt as active on the physical distributor
whenever the input to the GIC is asserted and conversely clear the
physical active state when the input to the GIC is deasserted.

Fourth, and finally, we now initialize the timer PPIs (and all the other
unused PPIs for now), to be level-triggered, and modify the sync code to
sample the line state on HW sync and re-inject a new interrupt if it is
still pending at that time.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22 23:01:44 +02:00
Christoffer Dall
d35268da66 arm/arm64: KVM: arch_timer: Only schedule soft timer on vcpu_block
We currently schedule a soft timer every time we exit the guest if the
timer did not expire while running the guest.  This is really not
necessary, because the only work we do in the timer work function is to
kick the vcpu.

Kicking the vcpu does two things:
(1) If the vpcu thread is on a waitqueue, make it runnable and remove it
from the waitqueue.
(2) If the vcpu is running on a different physical CPU from the one
doing the kick, it sends a reschedule IPI.

The second case cannot happen, because the soft timer is only ever
scheduled when the vcpu is not running.  The first case is only relevant
when the vcpu thread is on a waitqueue, which is only the case when the
vcpu thread has called kvm_vcpu_block().

Therefore, we only need to make sure a timer is scheduled for
kvm_vcpu_block(), which we do by encapsulating all calls to
kvm_vcpu_block() with kvm_timer_{un}schedule calls.

Additionally, we only schedule a soft timer if the timer is enabled and
unmasked, since it is useless otherwise.

Note that theoretically userspace can use the SET_ONE_REG interface to
change registers that should cause the timer to fire, even if the vcpu
is blocked without a scheduled timer, but this case was not supported
before this patch and we leave it for future work for now.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22 23:01:42 +02:00
Arnd Bergmann
4a5d69b739 KVM: arm: use GIC support unconditionally
The vgic code on ARM is built for all configurations that enable KVM,
but the parent_data field that it references is only present when
CONFIG_IRQ_DOMAIN_HIERARCHY is set:

virt/kvm/arm/vgic.c: In function 'kvm_vgic_map_phys_irq':
virt/kvm/arm/vgic.c:1781:13: error: 'struct irq_data' has no member named 'parent_data'

This flag is implied by the GIC driver, and indeed the VGIC code only
makes sense if a GIC is present. This changes the CONFIG_KVM symbol
to always select GIC, which avoids the issue.

Fixes: 662d971584 ("arm/arm64: KVM: Kill CONFIG_KVM_ARM_{VGIC,TIMER}")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-20 18:04:49 +02:00
Pavel Fedin
399ea0f6bc KVM: arm/arm64: Fix memory leak if timer initialization fails
Jump to correct label and free kvm_host_cpu_state

Reviewed-by: Wei Huang <wei@redhat.com>
Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-20 18:04:48 +02:00
Ming Lei
ef748917b5 arm/arm64: KVM: Remove 'config KVM_ARM_MAX_VCPUS'
This patch removes config option of KVM_ARM_MAX_VCPUS,
and like other ARCHs, just choose the maximum allowed
value from hardware, and follows the reasons:

1) from distribution view, the option has to be
defined as the max allowed value because it need to
meet all kinds of virtulization applications and
need to support most of SoCs;

2) using a bigger value doesn't introduce extra memory
consumption, and the help text in Kconfig isn't accurate
because kvm_vpu structure isn't allocated until request
of creating VCPU is sent from QEMU;

3) the main effect is that the field of vcpus[] in 'struct kvm'
becomes a bit bigger(sizeof(void *) per vcpu) and need more cache
lines to hold the structure, but 'struct kvm' is one generic struct,
and it has worked well on other ARCHs already in this way. Also,
the world switch frequecy is often low, for example, it is ~2000
when running kernel building load in VM from APM xgene KVM host,
so the effect is very small, and the difference can't be observed
in my test at all.

Cc: Dann Frazier <dann.frazier@canonical.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-17 13:13:27 +01:00
Marc Zyngier
688bc577ac arm: KVM: Disable virtual timer even if the guest is not using it
When running a guest with the architected timer disabled (with QEMU and
the kernel_irqchip=off option, for example), it is important to make
sure the timer gets turned off. Otherwise, the guest may try to
enable it anyway, leading to a screaming HW interrupt.

The fix is to unconditionally turn off the virtual timer on guest
exit.

Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-17 13:11:48 +01:00
Pavel Fedin
c2f58514cf arm/arm64: KVM: vgic: Check for !irqchip_in_kernel() when mapping resources
Until b26e5fdac4 ("arm/arm64: KVM: introduce per-VM ops"),
kvm_vgic_map_resources() used to include a check on irqchip_in_kernel(),
and vgic_v2_map_resources() still has it.

But now vm_ops are not initialized until we call kvm_vgic_create().
Therefore kvm_vgic_map_resources() can being called without a VGIC,
and we die because vm_ops.map_resources is NULL.

Fixing this restores QEMU's kernel-irqchip=off option to a working state,
allowing to use GIC emulation in userspace.

Fixes: b26e5fdac4 ("arm/arm64: KVM: introduce per-VM ops")
Cc: stable@vger.kernel.org
Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
[maz: reworked commit message]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-16 18:35:28 +01:00
Marek Majtyka
ca09f02f12 arm: KVM: Fix incorrect device to IPA mapping
A critical bug has been found in device memory stage1 translation for
VMs with more then 4GB of address space. Once vm_pgoff size is smaller
then pa (which is true for LPAE case, u32 and u64 respectively) some
more significant bits of pa may be lost as a shift operation is performed
on u32 and later cast onto u64.

Example: vm_pgoff(u32)=0x00210030, PAGE_SHIFT=12
        expected pa(u64):   0x0000002010030000
        produced pa(u64):   0x0000000010030000

The fix is to change the order of operations (casting first onto phys_addr_t
and then shifting).

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
[maz: fixed changelog and patch formatting]
Cc: stable@vger.kernel.org
Signed-off-by: Marek Majtyka <marek.majtyka@tieto.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-16 14:50:45 +01:00
Alexander Spyridakis
0c0672922d arm/arm64: KVM: Fix PSCI affinity info return value for non valid cores
If a guest requests the affinity info for a non-existing vCPU we need to
properly return an error, instead of erroneously reporting an off state.

Signed-off-by: Alexander Spyridakis <a.spyridakis@virtualopensystems.com>
Signed-off-by: Alvise Rigo <a.rigo@virtualopensystems.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-04 17:02:48 +01:00
Mario Smarduch
054167b3d5 arm: KVM: keep arm vfp/simd exit handling consistent with arm64
After enhancing arm64 FP/SIMD exit handling, ARMv7 VFP exit branch is moved
to guest trap handling. This allows us to keep exit handling flow between both
architectures consistent.

Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-08-19 22:27:58 +01:00
Marc Zyngier
f120cd6533 KVM: arm/arm64: timer: Allow the timer to control the active state
In order to remove the crude hack where we sneak the masked bit
into the timer's control register, make use of the phys_irq_map
API control the active state of the interrupt.

This causes some limited changes to allow for potential error
propagation.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-08-12 11:28:26 +01:00
Marc Zyngier
6c3d63c9a2 KVM: arm/arm64: vgic: Allow dynamic mapping of physical/virtual interrupts
In order to be able to feed physical interrupts to a guest, we need
to be able to establish the virtual-physical mapping between the two
worlds.

The mappings are kept in a set of RCU lists, indexed by virtual interrupts.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-08-12 11:28:25 +01:00
Marc Zyngier
abdf584383 arm/arm64: KVM: Move vgic handling to a non-preemptible section
As we're about to introduce some serious GIC-poking to the vgic code,
it is important to make sure that we're going to poke the part of
the GIC that belongs to the CPU we're about to run on (otherwise,
we'd end up with some unexpected interrupts firing)...

Introducing a non-preemptible section in kvm_arch_vcpu_ioctl_run
prevents the problem from occuring.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-08-12 11:28:23 +01:00
Marc Zyngier
9a99d05070 arm/arm64: KVM: Fix ordering of timer/GIC on guest entry
As we now inject the timer interrupt when we're about to enter
the guest, it makes a lot more sense to make sure this happens
before the vgic code queues the pending interrupts.

Otherwise, we get the interrupt on the following exit, which is
not great for latency (and leads to all kind of bizarre issues
when using with active interrupts at the HW level).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-08-12 11:28:23 +01:00
Alex Bennée
84e690bfbe KVM: arm64: introduce vcpu->arch.debug_ptr
This introduces a level of indirection for the debug registers. Instead
of using the sys_regs[] directly we store registers in a structure in
the vcpu. The new kvm_arm_reset_debug_ptr() sets the debug ptr to the
guest context.

Because we no longer give the sys_regs offset for the sys_reg_desc->reg
field, but instead the index into a debug-specific struct we need to
add a number of additional trap functions for each register. Also as the
generic generic user-space access code no longer works we have
introduced a new pair of function pointers to the sys_reg_desc structure
to override the generic code when needed.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-21 12:50:25 +01:00
Alex Bennée
56c7f5e77f KVM: arm: introduce kvm_arm_init/setup/clear_debug
This is a precursor for later patches which will need to do more to
setup debug state before entering the hyp.S switch code. The existing
functionality for setting mdcr_el2 has been moved out of hyp.S and now
uses the value kept in vcpu->arch.mdcr_el2.

As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've
had to add a mechanism to save the value of mdcr_el2 as a per-cpu
variable during the initialisation code. The kernel never sets this
number so we are assuming the bootcode has set up the correct value
here.

This also moves the conditional setting of the TDA bit from the hyp code
into the C code which is currently used for the lazy debug register
context switch code.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-21 12:47:08 +01:00
Alex Bennée
0e6f07f29c KVM: arm: guest debug, add stub KVM_SET_GUEST_DEBUG ioctl
This commit adds a stub function to support the KVM_SET_GUEST_DEBUG
ioctl. Any unsupported flag will return -EINVAL. For now, only
KVM_GUESTDBG_ENABLE is supported, although it won't have any effects.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>.
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-21 12:47:08 +01:00
Linus Torvalds
e8a0b37d28 Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM updates from Russell King:
 "Bigger items included in this update are:

   - A series of updates from Arnd for ARM randconfig build failures
   - Updates from Dmitry for StrongARM SA-1100 to move IRQ handling to
     drivers/irqchip/
   - Move ARMs SP804 timer to drivers/clocksource/
   - Perf updates from Mark Rutland in preparation to move the ARM perf
     code into drivers/ so it can be shared with ARM64.
   - MCPM updates from Nicolas
   - Add support for taking platform serial number from DT
   - Re-implement Keystone2 physical address space switch to conform to
     architecture requirements
   - Clean up ARMv7 LPAE code, which goes in hand with the Keystone2
     changes.
   - L2C cleanups to avoid unlocking caches if we're prevented by the
     secure support to unlock.
   - Avoid cleaning a potentially dirty cache containing stale data on
     CPU initialisation
   - Add ARM-only entry point for secondary startup (for machines that
     can only call into a Thumb kernel in ARM mode).  Same thing is also
     done for the resume entry point.
   - Provide arch_irqs_disabled via asm-generic
   - Enlarge ARMv7M vector table
   - Always use BFD linker for VDSO, as gold doesn't accept some of the
     options we need.
   - Fix an incorrect BSYM (for Thumb symbols) usage, and convert all
     BSYM compiler macros to a "badr" (for branch address).
   - Shut up compiler warnings provoked by our cmpxchg() implementation.
   - Ensure bad xchg sizes fail to link"

* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (75 commits)
  ARM: Fix build if CLKDEV_LOOKUP is not configured
  ARM: fix new BSYM() usage introduced via for-arm-soc branch
  ARM: 8383/1: nommu: avoid deprecated source register on mov
  ARM: 8391/1: l2c: add options to overwrite prefetching behavior
  ARM: 8390/1: irqflags: Get arch_irqs_disabled from asm-generic
  ARM: 8387/1: arm/mm/dma-mapping.c: Add arm_coherent_dma_mmap
  ARM: 8388/1: tcm: Don't crash when TCM banks are protected by TrustZone
  ARM: 8384/1: VDSO: force use of BFD linker
  ARM: 8385/1: VDSO: group link options
  ARM: cmpxchg: avoid warnings from macro-ized cmpxchg() implementations
  ARM: remove __bad_xchg definition
  ARM: 8369/1: ARMv7M: define size of vector table for Vybrid
  ARM: 8382/1: clocksource: make ARM_TIMER_SP804 depend on GENERIC_SCHED_CLOCK
  ARM: 8366/1: move Dual-Timer SP804 driver to drivers/clocksource
  ARM: 8365/1: introduce sp804_timer_disable and remove arm_timer.h inclusion
  ARM: 8364/1: fix BE32 module loading
  ARM: 8360/1: add secondary_startup_arm prototype in header file
  ARM: 8359/1: correct secondary_startup_arm mode
  ARM: proc-v7: sanitise and document registers around errata
  ARM: proc-v7: clean up MIDR access
  ...
2015-06-26 12:20:00 -07:00
Linus Torvalds
e3d8238d7f arm64 updates for 4.2, mostly refactoring/clean-up:
- CPU ops and PSCI (Power State Coordination Interface) refactoring
   following the merging of the arm64 ACPI support, together with
   handling of Trusted (secure) OS instances
 
 - Using fixmap for permanent FDT mapping, removing the initial dtb
   placement requirements (within 512MB from the start of the kernel
   image). This required moving the FDT self reservation out of the
   memreserve processing
 
 - Idmap (1:1 mapping used for MMU on/off) handling clean-up
 
 - Removing flush_cache_all() - not safe on ARM unless the MMU is off.
   Last stages of CPU power down/up are handled by firmware already
 
 - "Alternatives" (run-time code patching) refactoring and support for
   immediate branch patching, GICv3 CPU interface access
 
 - User faults handling clean-up
 
 And some fixes:
 
 - Fix for VDSO building with broken ELF toolchains
 
 - Fixing another case of init_mm.pgd usage for user mappings (during
   ASID roll-over broadcasting)
 
 - Fix for FPSIMD reloading after CPU hotplug
 
 - Fix for missing syscall trace exit
 
 - Workaround for .inst asm bug
 
 - Compat fix for switching the user tls tpidr_el0 register
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:
 "Mostly refactoring/clean-up:

   - CPU ops and PSCI (Power State Coordination Interface) refactoring
     following the merging of the arm64 ACPI support, together with
     handling of Trusted (secure) OS instances

   - Using fixmap for permanent FDT mapping, removing the initial dtb
     placement requirements (within 512MB from the start of the kernel
     image).  This required moving the FDT self reservation out of the
     memreserve processing

   - Idmap (1:1 mapping used for MMU on/off) handling clean-up

   - Removing flush_cache_all() - not safe on ARM unless the MMU is off.
     Last stages of CPU power down/up are handled by firmware already

   - "Alternatives" (run-time code patching) refactoring and support for
     immediate branch patching, GICv3 CPU interface access

   - User faults handling clean-up

  And some fixes:

   - Fix for VDSO building with broken ELF toolchains

   - Fix another case of init_mm.pgd usage for user mappings (during
     ASID roll-over broadcasting)

   - Fix for FPSIMD reloading after CPU hotplug

   - Fix for missing syscall trace exit

   - Workaround for .inst asm bug

   - Compat fix for switching the user tls tpidr_el0 register"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (42 commits)
  arm64: use private ratelimit state along with show_unhandled_signals
  arm64: show unhandled SP/PC alignment faults
  arm64: vdso: work-around broken ELF toolchains in Makefile
  arm64: kernel: rename __cpu_suspend to keep it aligned with arm
  arm64: compat: print compat_sp instead of sp
  arm64: mm: Fix freeing of the wrong memmap entries with !SPARSEMEM_VMEMMAP
  arm64: entry: fix context tracking for el0_sp_pc
  arm64: defconfig: enable memtest
  arm64: mm: remove reference to tlb.S from comment block
  arm64: Do not attempt to use init_mm in reset_context()
  arm64: KVM: Switch vgic save/restore to alternative_insn
  arm64: alternative: Introduce feature for GICv3 CPU interface
  arm64: psci: fix !CONFIG_HOTPLUG_CPU build warning
  arm64: fix bug for reloading FPSIMD state after CPU hotplug.
  arm64: kernel thread don't need to save fpsimd context.
  arm64: fix missing syscall trace exit
  arm64: alternative: Work around .inst assembler bugs
  arm64: alternative: Merge alternative-asm.h into alternative.h
  arm64: alternative: Allow immediate branch as alternative instruction
  arm64: Rework alternate sequence for ARM erratum 845719
  ...
2015-06-24 10:02:15 -07:00
Paolo Bonzini
05fe125fa3 KVM/ARM changes for v4.2:
- Proper guest time accounting
 - FP access fix for 32bit
 - The usual pile of GIC fixes
 - PSCI fixes
 - Random cleanups
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Merge tag 'kvm-arm-for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/ARM changes for v4.2:

- Proper guest time accounting
- FP access fix for 32bit
- The usual pile of GIC fixes
- PSCI fixes
- Random cleanups
2015-06-19 17:15:24 +02:00
Marc Zyngier
4642019dc4 arm/arm64: KVM: vgic: Do not save GICH_HCR / ICH_HCR_EL2
The GIC Hypervisor Configuration Register is used to enable
the delivery of virtual interupts to a guest, as well as to
define in which conditions maintenance interrupts are delivered
to the host.

This register doesn't contain any information that we need to
read back (the EOIcount is utterly useless for us).

So let's save ourselves some cycles, and not save it before
writing zero to it.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-06-17 09:59:55 +01:00
Lorenzo Pieralisi
e2d997366d ARM: kvm: psci: fix handling of unimplemented functions
According to the PSCI specification and the SMC/HVC calling
convention, PSCI function_ids that are not implemented must
return NOT_SUPPORTED as return value.

Current KVM implementation takes an unhandled PSCI function_id
as an error and injects an undefined instruction into the guest
if PSCI implementation is called with a function_id that is not
handled by the resident PSCI version (ie it is not implemented),
which is not the behaviour expected by a guest when calling a
PSCI function_id that is not implemented.

This patch fixes this issue by returning NOT_SUPPORTED whenever
the kvm PSCI call is executed for a function_id that is not
implemented by the PSCI kvm layer.

Cc: <stable@vger.kernel.org> # 3.18+
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-06-17 09:46:29 +01:00
Kim Phillips
8889583c03 KVM: arm/arm64: Enable the KVM-VFIO device
The KVM-VFIO device is used by the QEMU VFIO device. It is used to
record the list of in-use VFIO groups so that KVM can manipulate
them.

Signed-off-by: Kim Phillips <kim.phillips@linaro.org>
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-06-17 09:46:29 +01:00
Christoffer Dall
1b3d546daf arm/arm64: KVM: Properly account for guest CPU time
Until now we have been calling kvm_guest_exit after re-enabling
interrupts when we come back from the guest, but this has the
unfortunate effect that CPU time accounting done in the context of timer
interrupts occurring while the guest is running doesn't properly notice
that the time since the last tick was spent in the guest.

Inspired by the comment in the x86 code, move the kvm_guest_exit() call
below the local_irq_enable() call and change __kvm_guest_exit() to
kvm_guest_exit(), because we are now calling this function with
interrupts enabled.  We have to now explicitly disable preemption and
not enable preemption before we've called kvm_guest_exit(), since
otherwise we could be preempted and everything happening before we
eventually get scheduled again would be accounted for as guest time.

At the same time, move the trace_kvm_exit() call outside of the atomic
section, since there is no reason for us to do that with interrupts
disabled.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-06-17 09:46:28 +01:00
Tiejun Chen
ea2c6d9745 kvm: remove one useless check extension
We already check KVM_CAP_IRQFD in generic once enable CONFIG_HAVE_KVM_IRQFD,

kvm_vm_ioctl_check_extension_generic()
    |
    + switch (arg) {
    +   ...
    +   #ifdef CONFIG_HAVE_KVM_IRQFD
    +       case KVM_CAP_IRQFD:
    +   #endif
    +   ...
    +   return 1;
    +   ...
    + }
    |
    + kvm_vm_ioctl_check_extension()

So its not necessary to check this in arch again, and also fix one typo,
s/emlation/emulation.

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-06-17 09:46:28 +01:00
Marc Zyngier
85e84ba310 arm: KVM: force execution of HCPTR access on VM exit
On VM entry, we disable access to the VFP registers in order to
perform a lazy save/restore of these registers.

On VM exit, we restore access, test if we did enable them before,
and save/restore the guest/host registers if necessary. In this
sequence, the FPEXC register is always accessed, irrespective
of the trapping configuration.

If the guest didn't touch the VFP registers, then the HCPTR access
has now enabled such access, but we're missing a barrier to ensure
architectural execution of the new HCPTR configuration. If the HCPTR
access has been delayed/reordered, the subsequent access to FPEXC
will cause a trap, which we aren't prepared to handle at all.

The same condition exists when trapping to enable VFP for the guest.

The fix is to introduce a barrier after enabling VFP access. In the
vmexit case, it can be relaxed to only takes place if the guest hasn't
accessed its view of the VFP registers, making the access to FPEXC safe.

The set_hcptr macro is modified to deal with both vmenter/vmexit and
vmtrap operations, and now takes an optional label that is branched to
when the guest hasn't touched the VFP registers.

Reported-by: Vikram Sethi <vikrams@codeaurora.org>
Cc: stable@kernel.org	# v3.9+
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-06-17 09:40:14 +01:00
Firo Yang
a5f56ba3b4 ARM: KVM: Remove pointless void pointer cast
No need to cast the void pointer returned by kmalloc() in
arch/arm/kvm/mmu.c::kvm_alloc_stage2_pgd().

Signed-off-by: Firo Yang <firogm@gmail.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-06-09 18:05:17 +01:00
Paolo Bonzini
f36f3f2846 KVM: add "new" argument to kvm_arch_commit_memory_region
This lets the function access the new memory slot without going through
kvm_memslots and id_to_memslot.  It will simplify the code when more
than one address space will be supported.

Unfortunately, the "const"ness of the new argument must be casted
away in two places.  Fixing KVM to accept const struct kvm_memory_slot
pointers would require modifications in pretty much all architectures,
and is left for later.

Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-05-28 10:42:58 +02:00
Mark Rutland
538b9b25fa arm/arm64: kvm: add missing PSCI include
We make use of the PSCI function IDs, but don't explicitly include the
header which defines them. Relying on transitive header includes is
fragile and will be broken as headers are refactored.

This patch includes the relevant header file directly so as to avoid
future breakage.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
2015-05-27 13:21:16 +01:00
Paolo Bonzini
15f46015ee KVM: add memslots argument to kvm_arch_memslots_updated
Prepare for the case of multiple address spaces.

Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-05-26 12:40:17 +02:00
Paolo Bonzini
09170a4942 KVM: const-ify uses of struct kvm_userspace_memory_region
Architecture-specific helpers are not supposed to muck with
struct kvm_userspace_memory_region contents.  Add const to
enforce this.

In order to eliminate the only write in __kvm_set_memory_region,
the cleaning of deleted slots is pulled up from update_memslots
to __kvm_set_memory_region.

Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-05-26 12:40:13 +02:00
Paolo Bonzini
9f6b802978 KVM: use kvm_memslots whenever possible
kvm_memslots provides lockdep checking.  Use it consistently instead of
explicit dereferencing of kvm->memslots.

Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-05-26 12:40:08 +02:00