Commit Graph

1384 Commits

Author SHA1 Message Date
Marc Zyngier
be08c3cf3c Merge branch kvm-arm64/pkvm/fixed-features into kvmarm-master/next
* kvm-arm64/pkvm/fixed-features: (22 commits)
  : .
  : Add the pKVM fixed feature that allows a bunch of exceptions
  : to either be forbidden or be easily handled at EL2.
  : .
  KVM: arm64: pkvm: Give priority to standard traps over pvm handling
  KVM: arm64: pkvm: Pass vpcu instead of kvm to kvm_get_exit_handler_array()
  KVM: arm64: pkvm: Move kvm_handle_pvm_restricted around
  KVM: arm64: pkvm: Consolidate include files
  KVM: arm64: pkvm: Preserve pending SError on exit from AArch32
  KVM: arm64: pkvm: Handle GICv3 traps as required
  KVM: arm64: pkvm: Drop sysregs that should never be routed to the host
  KVM: arm64: pkvm: Drop AArch32-specific registers
  KVM: arm64: pkvm: Make the ERR/ERX*_EL1 registers RAZ/WI
  KVM: arm64: pkvm: Use a single function to expose all id-regs
  KVM: arm64: Fix early exit ptrauth handling
  KVM: arm64: Handle protected guests at 32 bits
  KVM: arm64: Trap access to pVM restricted features
  KVM: arm64: Move sanitized copies of CPU features
  KVM: arm64: Initialize trap registers for protected VMs
  KVM: arm64: Add handlers for protected VM System Registers
  KVM: arm64: Simplify masking out MTE in feature id reg
  KVM: arm64: Add missing field descriptor for MDCR_EL2
  KVM: arm64: Pass struct kvm to per-EC handlers
  KVM: arm64: Move early handlers to per-EC handlers
  ...

Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-10-18 17:20:50 +01:00
Marc Zyngier
0730559011 KVM: arm64: pkvm: Give priority to standard traps over pvm handling
Checking for pvm handling first means that we cannot handle ptrauth
traps or apply any of the workarounds (GICv3 or TX2 #219).

Flip the order around.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211013120346.2926621-12-maz@kernel.org
2021-10-18 16:57:09 +01:00
Marc Zyngier
0c7639cc83 KVM: arm64: pkvm: Pass vpcu instead of kvm to kvm_get_exit_handler_array()
Passing a VM pointer around is odd, and results in extra work on
VHE. Follow the rest of the design that uses the vcpu instead, and
let the nVHE code look into the struct kvm as required.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211013120346.2926621-11-maz@kernel.org
2021-10-18 16:57:09 +01:00
Marc Zyngier
746bdeadc5 KVM: arm64: pkvm: Move kvm_handle_pvm_restricted around
Place kvm_handle_pvm_restricted() next to its little friends such
as kvm_handle_pvm_sysreg().

This allows to make inject_undef64() static.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211013120346.2926621-10-maz@kernel.org
2021-10-18 16:57:09 +01:00
Marc Zyngier
3061725d16 KVM: arm64: pkvm: Consolidate include files
kvm_fixed_config.h is pkvm specific, and would be better placed
near its users. At the same time, include/nvhe/sys_regs.h is now
almost empty.

Merge the two into arch/arm64/kvm/hyp/include/nvhe/fixed_config.h.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211013120346.2926621-9-maz@kernel.org
2021-10-18 16:57:09 +01:00
Marc Zyngier
271b728605 KVM: arm64: pkvm: Preserve pending SError on exit from AArch32
Don't drop a potential SError when a guest gets caught red-handed
running AArch32 code.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211013120346.2926621-8-maz@kernel.org
2021-10-18 16:57:09 +01:00
Marc Zyngier
cbca197384 KVM: arm64: pkvm: Handle GICv3 traps as required
Forward accesses to the ICV_*SGI*_EL1 registers to EL1, and
emulate ICV_SRE_EL1 by returning a fixed value.

This should be enough to support GICv3 in a protected guest.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211013120346.2926621-7-maz@kernel.org
2021-10-18 16:57:09 +01:00
Marc Zyngier
f3d5ccabab KVM: arm64: pkvm: Drop sysregs that should never be routed to the host
A bunch of system registers (most of them MM related) should never
trap to the host under any circumstance. Keep them close to our chest.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211013120346.2926621-6-maz@kernel.org
2021-10-18 16:57:08 +01:00
Marc Zyngier
3c90cb15e2 KVM: arm64: pkvm: Drop AArch32-specific registers
All the SYS_*32_EL2 registers are AArch32-specific. Since we forbid
AArch32, there is no need to handle those in any way.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211013120346.2926621-5-maz@kernel.org
2021-10-18 16:57:08 +01:00
Marc Zyngier
8ffb418883 KVM: arm64: pkvm: Make the ERR/ERX*_EL1 registers RAZ/WI
The ERR*/ERX* registers should be handled as RAZ/WI, and there
should be no need to involve EL1 for that.

Add a helper that handles such registers, and repaint the sysreg
table to declare these registers as RAZ/WI.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211013120346.2926621-4-maz@kernel.org
2021-10-18 16:57:08 +01:00
Marc Zyngier
ce75916749 KVM: arm64: pkvm: Use a single function to expose all id-regs
Rather than exposing a whole set of helper functions to retrieve
individual ID registers, use the existing decoding tree and expose
a single helper instead.

This allow a number of functions to be made static, and we now
have a single entry point to maintain.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211013120346.2926621-3-maz@kernel.org
2021-10-18 16:57:08 +01:00
Marc Zyngier
8a049862c3 KVM: arm64: Fix early exit ptrauth handling
The previous rework of the early exit code to provide an EC-based
decoding tree missed the fact that we have two trap paths for
ptrauth: the instructions (EC_PAC) and the sysregs (EC_SYS64).

Rework the handlers to call the ptrauth handling code on both
paths.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211013120346.2926621-2-maz@kernel.org
2021-10-18 16:57:08 +01:00
Marc Zyngier
5f8b2591de Merge branch kvm-arm64/memory-accounting into kvmarm-master/next
* kvm-arm64/memory-accounting:
  : .
  : Sprinkle a bunch of GFP_KERNEL_ACCOUNT all over the code base
  : to better track memory allocation made on behalf of a VM.
  : .
  KVM: arm64: Add memcg accounting to KVM allocations
  KVM: arm64: vgic: Add memcg accounting to vgic allocations

Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-10-17 11:29:36 +01:00
Jia He
115bae923a KVM: arm64: Add memcg accounting to KVM allocations
Inspired by commit 254272ce65 ("kvm: x86: Add memcg accounting to KVM
allocations"), it would be better to make arm64 KVM consistent with
common kvm codes.

The memory allocations of VM scope should be charged into VM process
cgroup, hence change GFP_KERNEL to GFP_KERNEL_ACCOUNT.

There remain a few cases since these allocations are global, not in VM
scope.

Signed-off-by: Jia He <justin.he@arm.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210907123112.10232-3-justin.he@arm.com
2021-10-17 11:25:55 +01:00
Jia He
3ef231670b KVM: arm64: vgic: Add memcg accounting to vgic allocations
Inspired by commit 254272ce65 ("kvm: x86: Add memcg accounting to KVM
allocations"), it would be better to make arm64 vgic consistent with
common kvm codes.

The memory allocations of VM scope should be charged into VM process
cgroup, hence change GFP_KERNEL to GFP_KERNEL_ACCOUNT.

There remain a few cases since these allocations are global, not in VM
scope.

Signed-off-by: Jia He <justin.he@arm.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210907123112.10232-2-justin.he@arm.com
2021-10-17 11:25:55 +01:00
Marc Zyngier
20a3043075 Merge branch kvm-arm64/vgic-fixes-5.16 into kvmarm-master/next
* kvm-arm64/vgic-fixes-5.16:
  : .
  : Multiple updates to the GICv3 emulation in order to better support
  : the dreadful Apple M1 that only implements half of it, and in a
  : broken way...
  : .
  KVM: arm64: vgic-v3: Align emulated cpuif LPI state machine with the pseudocode
  KVM: arm64: vgic-v3: Don't advertise ICC_CTLR_EL1.SEIS
  KVM: arm64: vgic-v3: Reduce common group trapping to ICV_DIR_EL1 when possible
  KVM: arm64: vgic-v3: Work around GICv3 locally generated SErrors
  KVM: arm64: Force ID_AA64PFR0_EL1.GIC=1 when exposing a virtual GICv3

Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-10-17 11:10:14 +01:00
Marc Zyngier
9d449c71bd KVM: arm64: vgic-v3: Align emulated cpuif LPI state machine with the pseudocode
Having realised that a virtual LPI does transition through an active
state that does not exist on bare metal, align the CPU interface
emulation with the behaviour specified in the architecture pseudocode.

The LPIs now transition to active on IAR read, and to inactive on
EOI write. Special care is taken not to increment the EOIcount for
an LPI that isn't present in the LRs.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211010150910.2911495-6-maz@kernel.org
2021-10-17 11:06:36 +01:00
Marc Zyngier
f87ab68272 KVM: arm64: vgic-v3: Don't advertise ICC_CTLR_EL1.SEIS
Since we are trapping all sysreg accesses when ICH_VTR_EL2.SEIS
is set, and that we never deliver an SError when emulating
any of the GICv3 sysregs, don't advertise ICC_CTLR_EL1.SEIS.

Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211010150910.2911495-5-maz@kernel.org
2021-10-17 11:06:36 +01:00
Marc Zyngier
0924729b21 KVM: arm64: vgic-v3: Reduce common group trapping to ICV_DIR_EL1 when possible
On systems that advertise ICH_VTR_EL2.SEIS, we trap all GICv3 sysreg
accesses from the guest. From a performance perspective, this is OK
as long as the guest doesn't hammer the GICv3 CPU interface.

In most cases, this is fine, unless the guest actively uses
priorities and switches PMR_EL1 very often. Which is exactly what
happens when a Linux guest runs with irqchip.gicv3_pseudo_nmi=1.
In these condition, the performance plumets as we hit PMR each time
we mask/unmask interrupts. Not good.

There is however an opportunity for improvement. Careful reading
of the architecture specification indicates that the only GICv3
sysreg belonging to the common group (which contains the SGI
registers, PMR, DIR, CTLR and RPR) that is allowed to generate
a SError is DIR. Everything else is safe.

It is thus possible to substitute the trapping of all the common
group with just that of DIR if it supported by the implementation.
Yes, that's yet another optional bit of the architecture.
So let's just do that, as it leads to some impressive result on
the M1:

Without this change:
	bash-5.1# /host/home/maz/hackbench 100 process 1000
	Running with 100*40 (== 4000) tasks.
	Time: 56.596

With this change:
	bash-5.1# /host/home/maz/hackbench 100 process 1000
	Running with 100*40 (== 4000) tasks.
	Time: 8.649

which is a pretty convincing result.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Link: https://lore.kernel.org/r/20211010150910.2911495-4-maz@kernel.org
2021-10-17 11:06:36 +01:00
Marc Zyngier
df652bcf11 KVM: arm64: vgic-v3: Work around GICv3 locally generated SErrors
The infamous M1 has a feature nobody else ever implemented,
in the form of the "GIC locally generated SError interrupts",
also known as SEIS for short.

These SErrors are generated when a guest does something that violates
the GIC state machine. It would have been simpler to just *ignore*
the damned thing, but that's not what this HW does. Oh well.

This part of of the architecture is also amazingly under-specified.
There is a whole 10 lines that describe the feature in a spec that
is 930 pages long, and some of these lines are factually wrong.
Oh, and it is deprecated, so the insentive to clarify it is low.

Now, the spec says that this should be a *virtual* SError when
HCR_EL2.AMO is set. As it turns out, that's not always the case
on this CPU, and the SError sometimes fires on the host as a
physical SError. Goodbye, cruel world. This clearly is a HW bug,
and it means that a guest can easily take the host down, on demand.

Thankfully, we have seen systems that were just as broken in the
past, and we have the perfect vaccine for it.

Apple M1, please meet the Cavium ThunderX workaround. All your
GIC accesses will be trapped, sanitised, and emulated. Only the
signalling aspect of the HW will be used. It won't be super speedy,
but it will at least be safe. You're most welcome.

Given that this has only ever been seen on this single implementation,
that the spec is unclear at best and that we cannot trust it to ever
be implemented correctly, gate the workaround solely on ICH_VTR_EL2.SEIS
being set.

Tested-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211010150910.2911495-3-maz@kernel.org
2021-10-17 11:06:36 +01:00
Marc Zyngier
562e530fd7 KVM: arm64: Force ID_AA64PFR0_EL1.GIC=1 when exposing a virtual GICv3
Until now, we always let ID_AA64PFR0_EL1.GIC reflect the value
visible on the host, even if we were running a GICv2-enabled VM
on a GICv3+compat host.

That's fine, but we also now have the case of a host that does not
expose ID_AA64PFR0_EL1.GIC==1 despite having a vGIC. Yes, this is
confusing. Thank you M1.

Let's go back to first principles and expose ID_AA64PFR0_EL1.GIC=1
when a GICv3 is exposed to the guest. This also hides a GICv4.1
CPU interface from the guest which has no business knowing about
the v4.1 extension.

Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211010150910.2911495-2-maz@kernel.org
2021-10-17 11:06:36 +01:00
Fuad Tabba
5f39efc420 KVM: arm64: Handle protected guests at 32 bits
Protected KVM does not support protected AArch32 guests. However,
it is possible for the guest to force run AArch32, potentially
causing problems. Add an extra check so that if the hypervisor
catches the guest doing that, it can prevent the guest from
running again by resetting vcpu->arch.target and returning
ARM_EXCEPTION_IL.

If this were to happen, The VMM can try and fix it by re-
initializing the vcpu with KVM_ARM_VCPU_INIT, however, this is
likely not possible for protected VMs.

Adapted from commit 22f553842b ("KVM: arm64: Handle Asymmetric
AArch32 systems")

Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211010145636.1950948-12-tabba@google.com
2021-10-11 14:57:30 +01:00
Fuad Tabba
1423afcb41 KVM: arm64: Trap access to pVM restricted features
Trap accesses to restricted features for VMs running in protected
mode.

Access to feature registers are emulated, and only supported
features are exposed to protected VMs.

Accesses to restricted registers as well as restricted
instructions are trapped, and an undefined exception is injected
into the protected guests, i.e., with EC = 0x0 (unknown reason).
This EC is the one used, according to the Arm Architecture
Reference Manual, for unallocated or undefined system registers
or instructions.

Only affects the functionality of protected VMs. Otherwise,
should not affect non-protected VMs when KVM is running in
protected mode.

Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211010145636.1950948-11-tabba@google.com
2021-10-11 14:57:30 +01:00
Fuad Tabba
72e1be120e KVM: arm64: Move sanitized copies of CPU features
Move the sanitized copies of the CPU feature registers to the
recently created sys_regs.c. This consolidates all copies in a
more relevant file.

No functional change intended.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211010145636.1950948-10-tabba@google.com
2021-10-11 14:57:30 +01:00
Fuad Tabba
2a0c343386 KVM: arm64: Initialize trap registers for protected VMs
Protected VMs have more restricted features that need to be
trapped. Moreover, the host should not be trusted to set the
appropriate trapping registers and their values.

Initialize the trapping registers, i.e., hcr_el2, mdcr_el2, and
cptr_el2 at EL2 for protected guests, based on the values of the
guest's feature id registers.

No functional change intended as trap handlers introduced in the
previous patch are still not hooked in to the guest exit
handlers.

Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211010145636.1950948-9-tabba@google.com
2021-10-11 14:57:29 +01:00
Fuad Tabba
6c30bfb18d KVM: arm64: Add handlers for protected VM System Registers
Add system register handlers for protected VMs. These cover Sys64
registers (including feature id registers), and debug.

No functional change intended as these are not hooked in yet to
the guest exit handlers introduced earlier. So when trapping is
triggered, the exit handlers let the host handle it, as before.

Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211010145636.1950948-8-tabba@google.com
2021-10-11 14:57:29 +01:00
Fuad Tabba
16dd1fbb12 KVM: arm64: Simplify masking out MTE in feature id reg
Simplify code for hiding MTE support in feature id register when
MTE is not enabled/supported by KVM.

No functional change intended.

Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211010145636.1950948-7-tabba@google.com
2021-10-11 14:57:29 +01:00
Fuad Tabba
3b1a690eda KVM: arm64: Pass struct kvm to per-EC handlers
We need struct kvm to check for protected VMs to be able to pick
the right handlers for them in subsequent patches.

Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211010145636.1950948-5-tabba@google.com
2021-10-11 14:57:28 +01:00
Marc Zyngier
8fb2046180 KVM: arm64: Move early handlers to per-EC handlers
Simplify the early exception handling by slicing the gigantic decoding
tree into a more manageable set of functions, similar to what we have
in handle_exit.c.

This will also make the structure reusable for pKVM's own early exit
handling.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211010145636.1950948-4-tabba@google.com
2021-10-11 14:57:28 +01:00
Marc Zyngier
cc1e6fdfa9 KVM: arm64: Don't include switch.h into nvhe/kvm-main.c
hyp-main.c includes switch.h while it only requires adjust-pc.h.
Fix it to remove an unnecessary dependency.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211010145636.1950948-3-tabba@google.com
2021-10-11 14:57:27 +01:00
Marc Zyngier
7dd9b5a157 KVM: arm64: Move __get_fault_info() and co into their own include file
In order to avoid including the whole of the switching helpers
in unrelated files, move the __get_fault_info() and related helpers
into their own include file.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211010145636.1950948-2-tabba@google.com
2021-10-11 14:57:27 +01:00
Marc Zyngier
1eb07f4b68 Merge branch kvm-arm64/raz-sysregs into kvmarm-master/next
* kvm-arm64/raz-sysregs:
  : .
  : Simplify the handling of RAZ register, removing pointless indirections.
  : .
  KVM: arm64: Replace get_raz_id_reg() with get_raz_reg()
  KVM: arm64: Use get_raz_reg() for userspace reads of PMSWINC_EL0
  KVM: arm64: Return early from read_id_reg() if register is RAZ

Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-10-11 14:15:53 +01:00
Alexandru Elisei
ebf6aa8c04 KVM: arm64: Replace get_raz_id_reg() with get_raz_reg()
Reading a RAZ ID register isn't different from reading any other RAZ
register, so get rid of get_raz_id_reg() and replace it with get_raz_reg(),
which does the same thing, but does it without going through two layers of
indirection.

No functional change.

Suggested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211011105840.155815-4-alexandru.elisei@arm.com
2021-10-11 14:13:59 +01:00
Alexandru Elisei
5a43097623 KVM: arm64: Use get_raz_reg() for userspace reads of PMSWINC_EL0
PMSWINC_EL0 is a write-only register and was initially part of the VCPU
register state, but was later removed in commit 7a3ba3095a ("KVM:
arm64: Remove PMSWINC_EL0 shadow register"). To prevent regressions, the
register was kept accessible from userspace as Read-As-Zero (RAZ).

The read function that is used to handle userspace reads of this
register is get_raz_id_reg(), which, while technically correct, as it
returns 0, it is not semantically correct, as PMSWINC_EL0 is not an ID
register as the function name suggests.

Add a new function, get_raz_reg(), to use it as the accessor for
PMSWINC_EL0, as to not conflate get_raz_id_reg() to handle other types
of registers.

No functional change intended.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211011105840.155815-3-alexandru.elisei@arm.com
2021-10-11 14:13:59 +01:00
Alexandru Elisei
00d5101b25 KVM: arm64: Return early from read_id_reg() if register is RAZ
If read_id_reg() is called for an ID register which is Read-As-Zero (RAZ),
it initializes the return value to zero, then goes through a list of
registers which require special handling before returning the final value.

By not returning as soon as it checks that the register should be RAZ, the
function creates the opportunity for bugs, if, for example, a patch changes
a register to RAZ (like has happened with PMSWINC_EL0 in commit
11663111cd), but doesn't remove the special handling from read_id_reg();
or if a register is RAZ in certain situations, but readable in others.

Return early to make it impossible for a RAZ register to be anything other
than zero.

Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211011105840.155815-2-alexandru.elisei@arm.com
2021-10-11 14:13:58 +01:00
Marc Zyngier
a049cf7e63 Merge branch kvm-arm64/misc-5.16 into kvmarm-master/next
* kvm-arm64/misc-5.16:
  : .
  : - Allow KVM to be disabled from the command-line
  : - Clean up CONFIG_KVM vs CONFIG_HAVE_KVM
  : .
  KVM: arm64: Depend on HAVE_KVM instead of OF
  KVM: arm64: Unconditionally include generic KVM's Kconfig
  KVM: arm64: Allow KVM to be disabled from the command line

Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-10-11 10:14:38 +01:00
Sean Christopherson
e26bb75aa2 KVM: arm64: Depend on HAVE_KVM instead of OF
Select HAVE_KVM at all times on arm64, as the OF requirement is
always there (even in the case of an ACPI system, we still depend
on some of the OF infrastructure), and won't fo away.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Acked-by: Will Deacon <will@kernel.org>
[maz: Drop the "HAVE_KVM if OF" dependency, as OF is always there on arm64,
 new commit message]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210921222231.518092-3-seanjc@google.com
2021-10-11 10:08:50 +01:00
Sean Christopherson
c8f1e96734 KVM: arm64: Unconditionally include generic KVM's Kconfig
Unconditionally "source" the generic KVM Kconfig instead of wrapping it
with KVM=y.  A future patch will select HAVE_KVM so that referencing
HAVE_KVM in common kernel code doesn't break, and because KVM=y and
HAVE_KVM=n is weird.  Source the generic KVM Kconfig unconditionally so
that HAVE_KVM and KVM don't end up with a circular dependency.

Note, all but one of generic KVM's "configs" are of the HAVE_XYZ nature,
and the one outlier correctly takes a dependency on CONFIG_KVM, i.e. the
generic Kconfig is intended to be included unconditionally.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
[maz: made NVHE_EL2_DEBUG depend on KVM]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210921222231.518092-2-seanjc@google.com
2021-10-11 10:04:59 +01:00
Marc Zyngier
b6a68b97af KVM: arm64: Allow KVM to be disabled from the command line
Although KVM can be compiled out of the kernel, it cannot be disabled
at runtime. Allow this possibility by introducing a new mode that
will prevent KVM from initialising.

This is useful in the (limited) circumstances where you don't want
KVM to be available (what is wrong with you?), or when you want
to install another hypervisor instead (good luck with that).

Reviewed-by: David Brazdil <dbrazdil@google.com>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Andrew Scull <ascull@google.com>
Link: https://lore.kernel.org/r/20211001170553.3062988-1-maz@kernel.org
2021-10-11 09:48:47 +01:00
Marc Zyngier
15f9017c28 Merge branch kvm-arm64/vgic-ipa-checks into kvmarm-master/next
* kvm-arm64/vgic-ipa-checks:
  : .
  : Add extra checks to prevent ther various GIC regions to land
  : outside of the IPA space (and tests to verify that it works).
  : .
  KVM: arm64: selftests: Add init ITS device test
  KVM: arm64: selftests: Add test for legacy GICv3 REDIST base partially above IPA range
  KVM: arm64: selftests: Add tests for GIC redist/cpuif partially above IPA range
  KVM: arm64: selftests: Add some tests for GICv2 in vgic_init
  KVM: arm64: selftests: Make vgic_init/vm_gic_create version agnostic
  KVM: arm64: selftests: Make vgic_init gic version agnostic
  KVM: arm64: vgic: Drop vgic_check_ioaddr()
  KVM: arm64: vgic-v3: Check ITS region is not above the VM IPA size
  KVM: arm64: vgic-v2: Check cpu interface region is not above the VM IPA size
  KVM: arm64: vgic-v3: Check redist region is not above the VM IPA size
  kvm: arm64: vgic: Introduce vgic_check_iorange

Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-10-11 09:43:06 +01:00
Ricardo Koller
96e9038969 KVM: arm64: vgic: Drop vgic_check_ioaddr()
There are no more users of vgic_check_ioaddr(). Move its checks to
vgic_check_iorange() and then remove it.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211005011921.437353-6-ricarkol@google.com
2021-10-11 09:31:42 +01:00
Ricardo Koller
2ec02f6c64 KVM: arm64: vgic-v3: Check ITS region is not above the VM IPA size
Verify that the ITS region does not extend beyond the VM-specified IPA
range (phys_size).

  base + size > phys_size AND base < phys_size

Add the missing check into vgic_its_set_attr() which is called when
setting the region.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211005011921.437353-5-ricarkol@google.com
2021-10-11 09:31:42 +01:00
Ricardo Koller
c56a87da0a KVM: arm64: vgic-v2: Check cpu interface region is not above the VM IPA size
Verify that the GICv2 CPU interface does not extend beyond the
VM-specified IPA range (phys_size).

  base + size > phys_size AND base < phys_size

Add the missing check into kvm_vgic_addr() which is called when setting
the region. This patch also enables some superfluous checks for the
distributor (vgic_check_ioaddr was enough as alignment == size for the
distributors).

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211005011921.437353-4-ricarkol@google.com
2021-10-11 09:31:41 +01:00
Ricardo Koller
4612d98f58 KVM: arm64: vgic-v3: Check redist region is not above the VM IPA size
Verify that the redistributor regions do not extend beyond the
VM-specified IPA range (phys_size). This can happen when using
KVM_VGIC_V3_ADDR_TYPE_REDIST or KVM_VGIC_V3_ADDR_TYPE_REDIST_REGIONS
with:

  base + size > phys_size AND base < phys_size

Add the missing check into vgic_v3_alloc_redist_region() which is called
when setting the regions, and into vgic_v3_check_base() which is called
when attempting the first vcpu-run. The vcpu-run check does not apply to
KVM_VGIC_V3_ADDR_TYPE_REDIST_REGIONS because the regions size is known
before the first vcpu-run. Note that using the REDIST_REGIONS API
results in a different check, which already exists, at first vcpu run:
that the number of redist regions is enough for all vcpus.

Finally, this patch also enables some extra tests in
vgic_v3_alloc_redist_region() by calculating "size" early for the legacy
redist api: like checking that the REDIST region can fit all the already
created vcpus.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211005011921.437353-3-ricarkol@google.com
2021-10-11 09:31:41 +01:00
Ricardo Koller
f25c5e4daf kvm: arm64: vgic: Introduce vgic_check_iorange
Add the new vgic_check_iorange helper that checks that an iorange is
sane: the start address and size have valid alignments, the range is
within the addressable PA range, start+size doesn't overflow, and the
start wasn't already defined.

No functional change.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211005011921.437353-2-ricarkol@google.com
2021-10-11 09:31:41 +01:00
Will Deacon
057bed206f KVM: arm64: Disable privileged hypercalls after pKVM finalisation
After pKVM has been 'finalised' using the __pkvm_prot_finalize hypercall,
the calling CPU will have a Stage-2 translation enabled to prevent access
to memory pages owned by EL2.

Although this forms a significant part of the process to deprivilege the
host kernel, we also need to ensure that the hypercall interface is
reduced so that the EL2 code cannot, for example, be re-initialised using
a new set of vectors.

Re-order the hypercalls so that only a suffix remains available after
finalisation of pKVM.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211008135839.1193-7-will@kernel.org
2021-10-11 09:07:29 +01:00
Will Deacon
07036cffe1 KVM: arm64: Prevent re-finalisation of pKVM for a given CPU
__pkvm_prot_finalize() completes the deprivilege of the host when pKVM
is in use by installing a stage-2 translation table for the calling CPU.

Issuing the hypercall multiple times for a given CPU makes little sense,
but in such a case just return early with -EPERM rather than go through
the whole page-table dance again.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211008135839.1193-6-will@kernel.org
2021-10-11 09:07:29 +01:00
Will Deacon
2f2e1a5069 KVM: arm64: Propagate errors from __pkvm_prot_finalize hypercall
If the __pkvm_prot_finalize hypercall returns an error, we WARN but fail
to propagate the failure code back to kvm_arch_init().

Pass a pointer to a zero-initialised return variable so that failure
to finalise the pKVM protections on a host CPU can be reported back to
KVM.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211008135839.1193-5-will@kernel.org
2021-10-11 09:07:29 +01:00
Will Deacon
8579a185ba KVM: arm64: Reject stub hypercalls after pKVM has been initialised
The stub hypercalls provide mechanisms to reset and replace the EL2 code,
so uninstall them once pKVM has been initialised in order to ensure the
integrity of the hypervisor code.

To ensure pKVM initialisation remains functional, split cpu_hyp_reinit()
into two helper functions to separate usage of the stub from usage of
pkvm hypercalls either side of __pkvm_init on the boot CPU.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211008135839.1193-4-will@kernel.org
2021-10-11 09:07:28 +01:00
Marc Zyngier
e840f42a49 KVM: arm64: Fix PMU probe ordering
Russell reported that since 5.13, KVM's probing of the PMU has
started to fail on his HW. As it turns out, there is an implicit
ordering dependency between the architectural PMU probing code and
and KVM's own probing. If, due to probe ordering reasons, KVM probes
before the PMU driver, it will fail to detect the PMU and prevent it
from being advertised to guests as well as the VMM.

Obviously, this is one probing too many, and we should be able to
deal with any ordering.

Add a callback from the PMU code into KVM to advertise the registration
of a host CPU PMU, allowing for any probing order.

Fixes: 5421db1be3 ("KVM: arm64: Divorce the perf code from oprofile helpers")
Reported-by: "Russell King (Oracle)" <linux@armlinux.org.uk>
Tested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/YUYRKVflRtUytzy5@shell.armlinux.org.uk
Cc: stable@vger.kernel.org
2021-09-20 12:43:34 +01:00