Hi Peter,
On 28/03/18 20:55, Peter Maydell wrote:
> On 27 March 2018 at 15:04, Eric Auger wrote:
>> Now all the internals are ready to handle multiple redistributor
>> regions, let's allow the userspace to register them.
>>
>> Signed-off-by: Eric Auger
>> ---
>> virt/kvm/arm/vgic/vgic-kvm-devic
2018-03-28 13:51+0100, Marc Zyngier:
> Paolo, Radim,
>
> This is the (rather big) set of updates for KVM/ARM for v4.17. The
> main features are the set of VHE optimizations taking advantage of
> CPUs implementing ARMv8.1, together with the EL2 randomization patches
> that are the foundation for mi
On 27 March 2018 at 15:04, Eric Auger wrote:
> Now all the internals are ready to handle multiple redistributor
> regions, let's allow the userspace to register them.
>
> Signed-off-by: Eric Auger
> ---
> virt/kvm/arm/vgic/vgic-kvm-device.c | 40
> +++--
> virt/k
Hi kbuild test robot,
On 25/03/18 02:41, kbuild test robot wrote:
> I love your patch! Yet something to improve:
>
> [auto build test ERROR on pm/linux-next]
> [also build test ERROR on v4.16-rc6]
> [cannot apply to arm64/for-next/core next-20180323]
This is the potential conflict I referred to
Hi Borislav,
On 27/03/18 18:25, Borislav Petkov wrote:
> On Mon, Mar 19, 2018 at 02:29:13PM +, James Morse wrote:
>> I don't think the die_lock really helps here, do we really want to wait for a
>> remote CPU to finish printing an OOPs about user-space's bad memory accesses,
>> before we bring
Hi Marc,
On 26/03/18 18:49, Marc Zyngier wrote:
> On 22/03/18 18:14, James Morse wrote:
>> To ensure APEI always takes the same locks when processing a notification
>> we need the nmi-like callers to always call APEI in_nmi(). Add a helper
>> to do the work and claim the notification.
>>
>> When K
MIDR_ALL_VERSIONS is changing, and won't have the same meaning
in 4.17, and the right thing to use will be ERRATA_MIDR_ALL_VERSIONS.
In order to cope with the merge window, let's add a compatibility
macro that will allow a relatively smooth transition, and that
can be removed post 4.17-rc1.
Signe
Creates far too many conflicts with arm64/for-next/core, to be
resent post -rc1.
This reverts commit f9f5dc19509bbef6f5e675346f1a7d7b846bdb12.
Signed-off-by: Marc Zyngier
---
arch/arm64/include/asm/cpucaps.h | 2 +-
arch/arm64/include/asm/kvm_asm.h | 2 ++
arch/arm64/kernel/bpi.S |
vgic_copy_lpi_list() parses the LPI list and picks LPIs targeting
a given vcpu. We allocate the array containing the intids before taking
the lpi_list_lock, which means we can have an array size that is not
equal to the number of LPIs.
This is particularly obvious when looking at the path coming f
From: Shanker Donthineni
The function SMCCC_ARCH_WORKAROUND_1 was introduced as part of SMC
V1.1 Calling Convention to mitigate CVE-2017-5715. This patch uses
the standard call SMCCC_ARCH_WORKAROUND_1 for Falkor chips instead
of Silicon provider service ID 0xC2001700.
Cc: # 4.14+
Signed-off-by:
It was recently reported that VFIO mediated devices, and anything
that VFIO exposes as level interrupts, do no strictly follow the
expected logic of such interrupts as it only lowers the input
line when the guest has EOId the interrupt at the GIC level, rather
than when it Acked the interrupt at th
From: Peter Maydell
We have a KVM_REG_ARM encoding that we use to expose KVM guest registers
to userspace. Define that bit 28 in this encoding indicates secure vs
nonsecure, so we can distinguish the secure and nonsecure banked versions
of a banked AArch32 register.
For KVM currently, all guest
Cortex-A57 and A72 are vulnerable to the so-called "variant 3a" of
Meltdown, where an attacker can speculatively obtain the value
of a privileged system register.
By enabling ARM64_HARDEN_EL2_VECTORS on these CPUs, obtaining
VBAR_EL2 is not disclosing the hypervisor mappings anymore.
Acked-by: Ca
We're about to need to allocate hardening slots from other parts
of the kernel (in order to support ARM64_HARDEN_EL2_VECTORS).
Turn the counter into an atomic_t and make it available to the
rest of the kernel. Also add BP_HARDEN_EL2_SLOTS as the number of
slots instead of the hardcoded 4...
Acked
We're now ready to map our vectors in weird and wonderful locations.
On enabling ARM64_HARDEN_EL2_VECTORS, a vector slot gets allocated
if this hasn't been already done via ARM64_HARDEN_BRANCH_PREDICTOR
and gets mapped outside of the normal RAM region, next to the
idmap.
That way, being able to ob
So far, the branch from the vector slots to the main vectors can at
most be 4GB from the main vectors (the reach of ADRP), and this
distance is known at compile time. If we were to remap the slots
to an unrelated VA, things would break badly.
A way to achieve VA independence would be to load the a
Until now, all EL2 executable mappings were derived from their
EL1 VA. Since we want to decouple the vectors mapping from
the rest of the hypervisor, we need to be able to map some
text somewhere else.
The "idmap" region (for lack of a better name) is ideally suited
for this, as we have a huge ran
So far, we only reserve a single instruction in the BPI template in
order to branch to the vectors. As we're going to stuff a few more
instructions there, let's reserve a total of 5 instructions, which
we're going to patch later on as required.
We also introduce a small refactor of the vectors the
All our useful entry points into the hypervisor are starting by
saving x0 and x1 on the stack. Let's move those into the vectors
by introducing macros that annotate whether a vector is valid or
not, thus indicating whether we want to stash registers or not.
The only drawback is that we now also st
There is no reason why the BP hardening vectors shouldn't be part
of the HYP text at compile time, rather than being mapped at runtime.
Also introduce a new config symbol that controls the compilation
of bpi.S.
Acked-by: Catalin Marinas
Reviewed-by: Andrew Jones
Signed-off-by: Marc Zyngier
---
We currently provide the hyp-init code with a kernel VA, and expect
it to turn it into a HYP va by itself. As we're about to provide
the hypervisor with mappings that are not necessarily in the memory
range, let's move the kern_hyp_va macro to kvm_get_hyp_vector.
No functionnal change.
Acked-by:
The main idea behind randomising the EL2 VA is that we usually have
a few spare bits between the most significant bit of the VA mask
and the most significant bit of the linear mapping.
Those bits could be a bunch of zeroes, and could be useful
to move things around a bit. Of course, the more memor
Update the documentation to reflect the new tricks we play on the
EL2 mappings...
Acked-by: Christoffer Dall
Acked-by: Catalin Marinas
Signed-off-by: Marc Zyngier
---
Documentation/arm64/memory.txt | 8 +---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/Documentation/arm64/
As we're moving towards a much more dynamic way to compute our
HYP VA, let's express the mask in a slightly different way.
Instead of comparing the idmap position to the "low" VA mask,
we directly compute the mask by taking into account the idmap's
(VA_BIT-1) bit.
No functionnal change.
Acked-by
The encoder for ADD/SUB (immediate) can only cope with 12bit
immediates, while there is an encoding for a 12bit immediate shifted
by 12 bits to the left.
Let's fix this small oversight by allowing the LSL_12 bit to be set.
Reviewed-by: Christoffer Dall
Acked-by: Catalin Marinas
Signed-off-by: M
We so far mapped our HYP IO (which is essentially the GICv2 control
registers) using the same method as for memory. It recently appeared
that is a bit unsafe:
We compute the HYP VA using the kern_hyp_va helper, but that helper
is only designed to deal with kernel VAs coming from the linear map,
an
Unmapping the idmap range using 52bit PA is quite broken, as we
don't take into account the right number of PGD entries, and rely
on PTRS_PER_PGD. The result is that pgd_index() truncates the
address, and we end-up in the weed.
Let's introduce a new unmap_hyp_idmap_range() that knows about this,
t
Although the idmap section of KVM can only be at most 4kB and
must be aligned on a 4kB boundary, the rest of the code expects
it to be page aligned. Things get messy when tearing down the
HYP page tables when PAGE_SIZE is 64K, and the idmap section isn't
64K aligned.
Let's fix this by computing al
Add an encoder for the EXTR instruction, which also implements the ROR
variant (where Rn == Rm).
Acked-by: Catalin Marinas
Reviewed-by: Christoffer Dall
Signed-off-by: Marc Zyngier
---
arch/arm64/include/asm/insn.h | 6 ++
arch/arm64/kernel/insn.c | 32 +++
As we're about to change the way we map devices at HYP, we need
to move away from kern_hyp_va on an IO address.
One way of achieving this is to store the VAs in kvm_vgic_global_state,
and use that directly from the HYP code. This requires a small change
to create_hyp_io_mappings so that it can als
Both HYP io mappings call ioremap, followed by create_hyp_io_mappings.
Let's move the ioremap call into create_hyp_io_mappings itself, which
simplifies the code a bit and allows for further refactoring.
Reviewed-by: Christoffer Dall
Acked-by: Catalin Marinas
Signed-off-by: Marc Zyngier
---
arc
Displaying the HYP VA information is slightly counterproductive when
using VA randomization. Turn it into a debug feature only, and adjust
the last displayed value to reflect the top of RAM instead of ~0.
Acked-by: Christoffer Dall
Acked-by: Catalin Marinas
Signed-off-by: Marc Zyngier
---
virt
kvm_vgic_global_state is part of the read-only section, and is
usually accessed using a PC-relative address generation (adrp + add).
It is thus useless to use kern_hyp_va() on it, and actively problematic
if kern_hyp_va() becomes non-idempotent. On the other hand, there is
no way that the compiler
Now that we can dynamically compute the kernek/hyp VA mask, there
is no need for a feature flag to trigger the alternative patching.
Let's drop the flag and everything that depends on it.
Acked-by: Christoffer Dall
Acked-by: Catalin Marinas
Reviewed-by: Suzuki K Poulose
Signed-off-by: Marc Zyng
We lack a way to encode operations such as AND, ORR, EOR that take
an immediate value. Doing so is quite involved, and is all about
reverse engineering the decoding algorithm described in the
pseudocode function DecodeBitMasks().
This has been tested by feeding it all the possible literal values
a
So far, we're using a complicated sequence of alternatives to
patch the kernel/hyp VA mask on non-VHE, and NOP out the
masking altogether when on VHE.
The newly introduced dynamic patching gives us the opportunity
to simplify that code by patching a single instruction with
the correct mask (instea
We're missing the a way to generate the encoding of the N immediate,
which is only a single bit used in a number of instruction that take
an immediate.
Acked-by: Christoffer Dall
Reviewed-by: Catalin Marinas
Signed-off-by: Marc Zyngier
---
arch/arm64/include/asm/insn.h | 1 +
arch/arm64/kernel
We've so far relied on a patching infrastructure that only gave us
a single alternative, without any way to provide a range of potential
replacement instructions. For a single feature, this is an all or
nothing thing.
It would be interesting to have a more flexible grained way of patching
the kern
From: Christoffer Dall
We can finally get completely rid of any calls to the VGICv3
save/restore functions when the AP lists are empty on VHE systems. This
requires carefully factoring out trap configuration from saving and
restoring state, and carefully choosing what to do on the VHE and
non-VH
From: Christoffer Dall
The APRs can only have bits set when the guest acknowledges an interrupt
in the LR and can only have a bit cleared when the guest EOIs an
interrupt in the LR. Therefore, if we have no LRs with any
pending/active interrupts, the APR cannot change value and there is no
need
From: Christoffer Dall
The vgic-v2-sr.c file now only contains the logic to replay unaligned
accesses to the virtual CPU interface on 16K and 64K page systems, which
is only relevant on 64-bit platforms. Therefore move this file to the
arm64 KVM tree, remove the compile directive from the 32-bit
From: Christoffer Dall
Just like we can program the GICv2 hypervisor control interface directly
from the core vgic code, we can do the same for the GICv3 hypervisor
control interface on VHE systems.
We do this by simply calling the save/restore functions when we have VHE
and we can then get rid
From: Christoffer Dall
We can program the GICv2 hypervisor control interface logic directly
from the core vgic code and can instead do the save/restore directly
from the flush/sync functions, which can lead to a number of future
optimizations.
Signed-off-by: Christoffer Dall
Signed-off-by: Marc
From: Christoffer Dall
There is really no need to store the vgic_elrsr on the VGIC data
structures as the only need we have for the elrsr is to figure out if an
LR is inactive when we save the VGIC state upon returning from the
guest. We can might as well store this in a temporary local variable
From: Christoffer Dall
We do not have to change the c15 trap setting on each switch to/from the
guest on VHE systems, because this setting only affects guest EL1/EL0
(and therefore not the VHE host).
The PMU and debug trap configuration can also be done on vcpu load/put
instead, because they don
From: Christoffer Dall
There is no longer a need for an alternative to choose the right
function to tell us whether or not FPSIMD was enabled for the VM,
because we can simply can the appropriate functions directly from within
the _vhe and _nvhe run functions.
Reviewed-by: Marc Zyngier
Reviewed
From: Christoffer Dall
To make the code more readable and to avoid the overhead of a function
call, let's get rid of a pair of the alternative function selectors and
explicitly call the VHE and non-VHE functions using the has_vhe() static
key based selector instead, telling the compiler to try to
From: Christoffer Dall
As we are about to be more lazy with some of the trap configuration
register read/writes for VHE systems, move the logic that is currently
shared between VHE and non-VHE into a separate function which can be
called from either the world-switch path or from vcpu_load/vcpu_pu
From: Christoffer Dall
When running a 32-bit VM (EL1 in AArch32), the AArch32 system registers
can be deferred to vcpu load/put on VHE systems because neither
the host kernel nor host userspace uses these registers.
Note that we can't save DBGVCR32_EL2 conditionally based on the state of
the deb
From: Christoffer Dall
Some system registers do not affect the host kernel's execution and can
therefore be loaded when we are about to run a VCPU and we don't have to
restore the host state to the hardware before the time when we are
actually about to return to userspace or schedule out the VCPU
From: Christoffer Dall
32-bit registers are not used by a 64-bit host kernel and can be
deferred, but we need to rework the accesses to these register to access
the latest values depending on whether or not guest system registers are
loaded on the CPU or only reside in memory.
Reviewed-by: Marc
From: Christoffer Dall
SPSR_EL1 is not used by a VHE host kernel and can be deferred, but we
need to rework the accesses to this register to access the latest value
depending on whether or not guest system registers are loaded on the CPU
or only reside in memory.
The handling of accessing the va
From: Christoffer Dall
ELR_EL1 is not used by a VHE host kernel and can be deferred, but we
need to rework the accesses to this register to access the latest value
depending on whether or not guest system registers are loaded on the CPU
or only reside in memory.
Reviewed-by: Marc Zyngier
Review
From: Christoffer Dall
We are about to defer saving and restoring some groups of system
registers to vcpu_put and vcpu_load on supported systems. This means
that we need some infrastructure to access system registes which
supports either accessing the memory backing of the register or directly
a
From: Christoffer Dall
Currently we access the system registers array via the vcpu_sys_reg()
macro. However, we are about to change the behavior to some times
modify the register file directly, so let's change this to two
primitives:
* Accessor macros vcpu_write_sys_reg() and vcpu_read_sys_reg
From: Christoffer Dall
We currently handle 32-bit accesses to trapped VM system registers using
the 32-bit index into the coproc array on the vcpu structure, which is a
union of the coproc array and the sysreg array.
Since all the 32-bit coproc indices are created to correspond to the
architectu
From: Christoffer Dall
On non-VHE systems we need to save the ELR_EL2 and SPSR_EL2 so that we can
return to the host in EL1 in the same state and location where we issued a
hypercall to EL2, but on VHE ELR_EL2 and SPSR_EL2 are not useful because we
never enter a guest as a result of an exception
From: Christoffer Dall
There is no need to have multiple identical functions with different
names for saving host and guest state. When saving and restoring state
for the host and guest, the state is the same for both contexts, and
that's why we have the kvm_cpu_context structure. Delete one
ve
From: Christoffer Dall
The comment only applied to SPE on non-VHE systems, so we simply remove
it.
Suggested-by: Andrew Jones
Acked-by: Marc Zyngier
Reviewed-by: Andrew Jones
Signed-off-by: Christoffer Dall
Signed-off-by: Marc Zyngier
---
arch/arm64/kvm/hyp/switch.c | 4
1 file change
From: Christoffer Dall
As we are about to handle system registers quite differently between VHE
and non-VHE systems. In preparation for that, we need to split some of
the handling functions between VHE and non-VHE functionality.
For now, we simply copy the non-VHE functions, but we do change th
From: Christoffer Dall
As we are about to move calls around in the sysreg save/restore logic,
let's first rewrite the alternative function callers, because it is
going to make the next patches much easier to read.
Acked-by: Marc Zyngier
Reviewed-by: Andrew Jones
Signed-off-by: Christoffer Dall
From: Christoffer Dall
There's a semantic difference between the EL1 registers that control
operation of a kernel running in EL1 and EL1 registers that only control
userspace execution in EL0. Since we can defer saving/restoring the
latter, move them into their own function.
The ARMv8 ARM (ARM
From: Christoffer Dall
The VHE switch function calls __timer_enable_traps and
__timer_disable_traps which don't do anything on VHE systems.
Therefore, simply remove these calls from the VHE switch function and
make the functions non-conditional as they are now only called from the
non-VHE switch
From: Christoffer Dall
There is no need to reset the VTTBR to zero when exiting the guest on
VHE systems. VHE systems don't use stage 2 translations for the EL2&0
translation regime used by the host.
Reviewed-by: Andrew Jones
Acked-by: Marc Zyngier
Signed-off-by: Christoffer Dall
Signed-off-
From: Christoffer Dall
VHE kernels run completely in EL2 and therefore don't have a notion of
kernel and hyp addresses, they are all just kernel addresses. Therefore
don't call kern_hyp_va() in the VHE switch function.
Reviewed-by: Andrew Jones
Reviewed-by: Marc Zyngier
Signed-off-by: Christo
From: Christoffer Dall
Instead of having multiple calls from the world switch path to the debug
logic, each figuring out if the dirty bit is set and if we should
save/restore the debug registers, let's just provide two hooks to the
debug save/restore functionality, one for switching to the guest
From: Christoffer Dall
So far this is mostly (see below) a copy of the legacy non-VHE switch
function, but we will start reworking these functions in separate
directions to work on VHE and non-VHE in the most optimal way in later
patches.
The only difference after this patch between the VHE and
From: Christoffer Dall
The current world-switch function has functionality to detect a number
of cases where we need to fixup some part of the exit condition and
possibly run the guest again, before having restored the host state.
This includes populating missing fault info, emulating GICv2 CPU
From: Christoffer Dall
The debug save/restore functions can be improved by using the has_vhe()
static key instead of the instruction alternative. Using the static key
uses the same paradigm as we're going to use elsewhere, it makes the
code more readable, and it generates slightly better code (n
From: Christoffer Dall
We have numerous checks around that checks if the HCR_EL2 has the RW bit
set to figure out if we're running an AArch64 or AArch32 VM. In some
cases, directly checking the RW bit (given its unintuitive name), is a
bit confusing, and that's not going to improve as we move lo
From: Christoffer Dall
As we are about to move a bunch of save/restore logic for VHE kernels to
the load and put functions, we need some infrastructure to do this.
Reviewed-by: Andrew Jones
Acked-by: Marc Zyngier
Signed-off-by: Christoffer Dall
Signed-off-by: Marc Zyngier
---
arch/arm/inclu
From: Christoffer Dall
There is no need to figure out inside the world-switch if we should
save/restore the debug registers or not, we might as well do that in the
higher level debug setup code, making it easier to optimize down the
line.
Reviewed-by: Julien Thierry
Reviewed-by: Marc Zyngier
R
From: Christoffer Dall
VHE actually doesn't rely on clearing the VTTBR when returning to the
host kernel, and that is the current key mechanism of hyp_panic to
figure out how to attempt to return to a state good enough to print a
panic statement.
Therefore, we split the hyp_panic function into t
From: Christoffer Dall
We currently have a separate read-modify-write of the HCR_EL2 on entry
to the guest for the sole purpose of setting the VF and VI bits, if set.
Since this is most rarely the case (only when using userspace IRQ chip
and interrupts are in flight), let's get rid of this operat
From: Shih-Wei Li
We always set the IMO and FMO bits in the HCR_EL2 when running the
guest, regardless if we use the vgic or not. By moving these flags to
HCR_GUEST_FLAGS we can avoid one of the extra save/restore operations of
HCR_EL2 in the world switch code, and we can also soon get rid of th
From: Christoffer Dall
We already have the percpu area for the host cpu state, which points to
the VCPU, so there's no need to store the VCPU pointer on the stack on
every context switch. We can be a little more clever and just use
tpidr_el2 for the percpu offset and load the VCPU pointer from t
From: Christoffer Dall
Moving the call to vcpu_load() in kvm_arch_vcpu_ioctl_run() to after
we've called kvm_vcpu_first_run_init() simplifies some of the vgic and
there is also no need to do vcpu_load() for things such as handling the
immediate_exit flag.
Reviewed-by: Julien Grall
Reviewed-by:
From: Christoffer Dall
Calling vcpu_load() registers preempt notifiers for this vcpu and calls
kvm_arch_vcpu_load(). The latter will soon be doing a lot of heavy
lifting on arm/arm64 and will try to do things such as enabling the
virtual timer and setting us up to handle interrupts from the time
The vgic code is trying to be clever when injecting GICv2 SGIs,
and will happily populate LRs with the same interrupt number if
they come from multiple vcpus (after all, they are distinct
interrupt sources).
Unfortunately, this is against the letter of the architecture,
and the GICv2 architecture
On guest exit, and when using GICv2 on GICv3, we use a dsb(st) to
force synchronization between the memory-mapped guest view and
the system-register view that the hypervisor uses.
This is incorrect, as the spec calls out the need for "a DSB whose
required access type is both loads and stores with
From: Ard Biesheuvel
On my GICv3 system, the following is printed to the kernel log at boot:
kvm [1]: 8-bit VMID
kvm [1]: IDMAP page: d20e35000
kvm [1]: HYP VA range: 8000:
kvm [1]: vgic-v2@2c02
kvm [1]: GIC system register CPU interface enabled
kvm [1]:
From: Christoffer Dall
We currently don't allow resetting mapped IRQs from userspace, because
their state is controlled by the hardware. But we do need to reset the
state when the VM is reset, so we provide a function for the 'owner' of
the mapped interrupt to reset the interrupt state.
Current
From: Christoffer Dall
Calling vcpu_load() registers preempt notifiers for this vcpu and calls
kvm_arch_vcpu_load(). The latter will soon be doing a lot of heavy
lifting on arm/arm64 and will try to do things such as enabling the
virtual timer and setting us up to handle interrupts from the time
From: Andre Przywara
Our irq_is_pending() helper function accesses multiple members of the
vgic_irq struct, so we need to hold the lock when calling it.
Add that requirement as a comment to the definition and take the lock
around the call in vgic_mmio_read_pending(), where we were missing it
befo
From: Shanker Donthineni
In AArch64/AArch32, the virtual counter uses a fixed virtual offset
of zero in the following situations as per ARMv8 specifications:
1) HCR_EL2.E2H is 1, and CNTVCT_EL0/CNTVCT are read from EL2.
2) HCR_EL2.{E2H, TGE} is {1, 1}, and either:
— CNTVCT_EL0 is read from No
From: Jérémy Fanguède
Set the handlers to emulate read and write operations for CNTP_CTL,
CNTP_CVAL and CNTP_TVAL registers in such a way that VMs can use the
physical timer.
Signed-off-by: Jérémy Fanguède
Signed-off-by: Christoffer Dall
---
arch/arm/kvm/coproc.c | 61
From: Jérémy Fanguède
Some 32bits guest OS can use the CNTP timer, however KVM does not
handle the accesses, injecting a fault instead.
Use the proper handlers to emulate the EL1 Physical Timer (CNTP)
register accesses of AArch32 guests.
Signed-off-by: Jérémy Fanguède
Signed-off-by: Alvise Rig
From: Mark Rutland
We don't currently limit guest accesses to the LOR registers, which we
neither virtualize nor context-switch. As such, guests are provided with
unusable information/controls, and are not isolated from each other (or
the host).
To prevent these issues, we can trap register acce
From: Dave Martin
The HCR_EL2.TID3 flag needs to be set when trapping guest access to
the CPU ID registers is required. However, the decision about
whether to set this bit does not need to be repeated at every
switch to the guest.
Instead, it's sufficient to make this decision once and record t
From: Arnd Bergmann
In banked-sr.c, we use a top-level '__asm__(".arch_extension virt")'
statement to allow compilation of a multi-CPU kernel for ARMv6
and older ARMv7-A that don't normally support access to the banked
registers.
This is considered to be a programming error by the gcc developers
Paolo, Radim,
This is the (rather big) set of updates for KVM/ARM for v4.17. The
main features are the set of VHE optimizations taking advantage of
CPUs implementing ARMv8.1, together with the EL2 randomization patches
that are the foundation for mitigating the so-called variant 3a
security issue
From: Christoffer Dall
When introducing support for irqchip in userspace we needed a way to
mask the timer signal to prevent the guest continuously exiting due to a
screaming timer.
We did this by disabling the corresponding percpu interrupt on the
host interrupt controller, because we cannot re
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