Commit Graph

45 Commits

Author SHA1 Message Date
Oliver Upton
1f315e99bd Merge branch 'kvm-arm64/gcie-legacy' into kvmarm/next
* kvm-arm64/gcie-legacy:
  : Support for GICv3 emulation on GICv5, courtesy of Sascha Bischoff
  :
  : FEAT_GCIE_LEGACY adds the necessary hardware for GICv5 systems to
  : support the legacy GICv3 for VMs, including a backwards-compatible VGIC
  : implementation that we all know and love.
  :
  : As a starting point for GICv5 enablement in KVM, enable + use the
  : GICv3-compatible feature when running VMs on GICv5 hardware.
  KVM: arm64: gic-v5: Probe for GICv5
  KVM: arm64: gic-v5: Support GICv3 compat
  arm64/sysreg: Add ICH_VCTLR_EL2
  irqchip/gic-v5: Populate struct gic_kvm_info
  irqchip/gic-v5: Skip deactivate for forwarded PPI interrupts

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-26 08:50:06 -07:00
Sascha Bischoff
c017e49ed1 KVM: arm64: gic-v5: Support GICv3 compat
Add support for GICv3 compat mode (FEAT_GCIE_LEGACY) which allows a
GICv5 host to run GICv3-based VMs. This change enables the
VHE/nVHE/hVHE/protected modes, but does not support nested
virtualization.

A lazy-disable approach is taken for compat mode; it is enabled on the
vgic_v3_load path but not disabled on the vgic_v3_put path. A
non-GICv3 VM, i.e., one based on GICv5, is responsible for disabling
compat mode on the corresponding vgic_v5_load path. Currently, GICv5
is not supported, and hence compat mode is not disabled again once it
is enabled, and this function is intentionally omitted from the code.

Co-authored-by: Timothy Hayes <timothy.hayes@arm.com>
Signed-off-by: Timothy Hayes <timothy.hayes@arm.com>
Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Link: https://lore.kernel.org/r/20250627100847.1022515-5-sascha.bischoff@arm.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-08 14:41:06 -07:00
Marc Zyngier
1d6fea7663 KVM: arm64: Add helper to identify a nested context
A common idiom in the KVM code is to check if we are currently
dealing with a "nested" context, defined as having NV enabled,
but being in the EL1&0 translation regime.

This is usually expressed as:

	if (vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu) ... )

which is a mouthful and a bit hard to read, specially when followed
by additional conditions.

Introduce a new helper that encapsulate these two terms, allowing
the above to be written as

	if (is_nested_context(vcpu) ... )

which is both shorter and easier to read, and makes more obvious
the potential for simplification on some code paths.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250708172532.1699409-4-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-08 10:40:30 -07:00
Marc Zyngier
1b85d923ba Merge branch kvm-arm64/misc-6.16 into kvmarm-master/next
* kvm-arm64/misc-6.16:
  : .
  : Misc changes and improvements for 6.16:
  :
  : - Add a new selftest for the SVE host state being corrupted by a guest
  :
  : - Keep HCR_EL2.xMO set at all times for systems running with the kernel at EL2,
  :   ensuring that the window for interrupts is slightly bigger, and avoiding
  :   a pretty bad erratum on the AmpereOne HW
  :
  : - Replace a couple of open-coded on/off strings with str_on_off()
  :
  : - Get rid of the pKVM memblock sorting, which now appears to be superflous
  :
  : - Drop superflous clearing of ICH_LR_EOI in the LR when nesting
  :
  : - Add workaround for AmpereOne's erratum AC04_CPU_23, which suffers from
  :   a pretty bad case of TLB corruption unless accesses to HCR_EL2 are
  :   heavily synchronised
  :
  : - Add a per-VM, per-ITS debugfs entry to dump the state of the ITS tables
  :   in a human-friendly fashion
  : .
  KVM: arm64: Fix documentation for vgic_its_iter_next()
  KVM: arm64: vgic-its: Add debugfs interface to expose ITS tables
  arm64: errata: Work around AmpereOne's erratum AC04_CPU_23
  KVM: arm64: nv: Remove clearing of ICH_LR<n>.EOI if ICH_LR<n>.HW == 1
  KVM: arm64: Drop sort_memblock_regions()
  KVM: arm64: selftests: Add test for SVE host corruption
  KVM: arm64: Force HCR_EL2.xMO to 1 at all times in VHE mode
  KVM: arm64: Replace ternary flags with str_on_off() helper

Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-23 10:59:43 +01:00
D Scott Phillips
fed55f49fa arm64: errata: Work around AmpereOne's erratum AC04_CPU_23
On AmpereOne AC04, updates to HCR_EL2 can rarely corrupt simultaneous
translations for data addresses initiated by load/store instructions.
Only instruction initiated translations are vulnerable, not translations
from prefetches for example. A DSB before the store to HCR_EL2 is
sufficient to prevent older instructions from hitting the window for
corruption, and an ISB after is sufficient to prevent younger
instructions from hitting the window for corruption.

Signed-off-by: D Scott Phillips <scott@os.amperecomputing.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20250513184514.2678288-1-scott@os.amperecomputing.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-19 12:46:26 +01:00
Marc Zyngier
0f013a524b arm64: sysreg: Replace HFGxTR_EL2 with HFG{R,W}TR_EL2
Treating HFGRTR_EL2 and HFGWTR_EL2 identically was a mistake.
It makes things hard to reason about, has the potential to
introduce bugs by giving a meaning to bits that are really reserved,
and is in general a bad description of the architecture.

Given that #defines are cheap, let's describe both registers as
intended by the architecture, and repaint all the existing uses.

Yes, this is painful.

The registers themselves are generated from the JSON file in
an automated way.

Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-06 17:35:03 +01:00
Marc Zyngier
bae247ccad KVM: arm64: Force HCR_EL2.xMO to 1 at all times in VHE mode
We keep setting and clearing these bits depending on the role of
the host kernel, mimicking what we do for nVHE. But that's actually
pretty pointless, as we always want physical interrupts to make it
to the host, at EL2.

This has also two problems:

- it prevents IRQs from being taken when these bits are cleared
  if the implementation has chosen to implement these bits as
  masks when HCR_EL2.{TGE,xMO}=={0,0}

- it triggers a bad erratum on the AmpereOne HW, which catches
  fire on clearing these bits while an interrupt is being taken
  (AC03_CPU_36).

Let's kill these two birds with a single stone, and permanently
set the xMO bits when running VHE. This involves a bit of surgery
on code paths that rely on flipping these bits on and off for
other purposes.

Note that the earliest setting of hcr_el2 (in the init_hcr_el2
macro) is left untouched as is runs extremely early, with interrupts
disabled, and soon enough overwritten with the final value containing
the xMO bits.

Reported-by: D Scott Phillips <scott@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20250429114326.3618875-1-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-06 09:41:32 +01:00
Marc Zyngier
146a050f2d KVM: arm64: nv: Nested GICv3 emulation
When entering a nested VM, we set up the hypervisor control interface
based on what the guest hypervisor has set. Especially, we investigate
each list register written by the guest hypervisor whether HW bit is
set.  If so, we translate hw irq number from the guest's point of view
to the real hardware irq number if there is a mapping.

Co-developed-by: Jintack Lim <jintack@cs.columbia.edu>
Signed-off-by: Jintack Lim <jintack@cs.columbia.edu>
[Christoffer: Redesigned execution flow around vcpu load/put]
Co-developed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
[maz: Rewritten to support GICv3 instead of GICv2, NV2 support]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250225172930.1850838-9-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-03 14:57:04 -08:00
Marc Zyngier
22513c0d2a arm64: sysreg: Add layout for ICH_HCR_EL2
The ICH_HCR_EL2-related macros are missing a number of control
bits that we are about to handle. Take this opportunity to fully
describe the layout of that register as part of the automatic
generation infrastructure.

This results in a bit of churn, unfortunately.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250225172930.1850838-2-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-03 14:51:51 -08:00
Will Deacon
ad361ed477 KVM: arm64: Just advertise SEIS as 0 when emulating ICC_CTLR_EL1
ICC_CTLR_EL1 accesses from a guest are trapped and emulated on systems
with broken SEIS support and without FEAT_GICv3_TDIR. On such systems,
we mask SEIS support in 'kvm_vgic_global_state.ich_vtr_el2' and so the
value of ICC_CTLR_EL1.SEIS visible to the guest is always zero.

Simplify the ICC_CTLR_EL1 read emulation to return 0 for the SEIS field,
rather than reading an always-zero value from the global state.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241022144016.27350-2-will@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-10-23 23:21:45 +00:00
Marc Zyngier
4a999a1d7a KVM: arm64: Make most GICv3 accesses UNDEF if they trap
We don't expect to trap any GICv3 register for host handling,
apart from ICC_SRE_EL1 and the SGI registers. If they trap,
that's because the guest is playing with us despite being
told it doesn't have a GICv3.

If it does, UNDEF is what it will get.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240827152517.3909653-10-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-08-27 18:32:56 +01:00
Marc Zyngier
59af011d00 KVM: arm64: Honor guest requested traps in GICv3 emulation
On platforms that require emulation of the CPU interface, we still
need to honor the traps requested by the guest (ICH_HCR_EL2 as well
as the FGTs for ICC_IGRPEN{0,1}_EL1.

Check for these bits early and lail out if any trap applies.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240827152517.3909653-9-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-08-27 18:32:55 +01:00
Marc Zyngier
5739a961b5 KVM: arm64: Force SRE traps when SRE access is not enabled
We so far only write the ICH_HCR_EL2 config in two situations:

- when we need to emulate the GICv3 CPU interface due to HW bugs

- when we do direct injection, as the virtual CPU interface needs
  to be enabled

This is all good. But it also means that we don't do anything special
when we emulate a GICv2, or that there is no GIC at all.

What happens in this case when the guest uses the GICv3 system
registers? The *guest* gets a trap for a sysreg access (EC=0x18)
while we'd really like it to get an UNDEF.

Fixing this is a bit involved:

- we need to set all the required trap bits (TC, TALL0, TALL1, TDIR)

- for these traps to take effect, we need to (counter-intuitively)
  set ICC_SRE_EL1.SRE to 1 so that the above traps take priority.

Note that doesn't fully work when GICv2 emulation is enabled, as
we cannot set ICC_SRE_EL1.SRE to 1 (it breaks Group0 delivery as
IRQ).

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240827152517.3909653-3-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-08-27 18:32:55 +01:00
Marc Zyngier
948e1a53c2 KVM: arm64: Simplify vgic-v3 hypercalls
Consolidate the GICv3 VMCR accessor hypercalls into the APR save/restore
hypercalls so that all of the EL2 GICv3 state is covered by a single pair
of hypercalls.

Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-17-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-01 16:48:14 +01:00
Alexandru Elisei
0b12620fdd KVM: arm64: Treat ESR_EL2 as a 64-bit register
ESR_EL2 was defined as a 32-bit register in the initial release of the
ARM Architecture Manual for Armv8-A, and was later extended to 64 bits,
with bits [63:32] RES0. ARMv8.7 introduced FEAT_LS64, which makes use of
bits [36:32].

KVM treats ESR_EL1 as a 64-bit register when saving and restoring the
guest context, but ESR_EL2 is handled as a 32-bit register. Start
treating ESR_EL2 as a 64-bit register to allow KVM to make use of the
most significant 32 bits in the future.

The type chosen to represent ESR_EL2 is u64, as that is consistent with the
notation KVM overwhelmingly uses today (u32), and how the rest of the
registers are declared.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220425114444.368693-5-alexandru.elisei@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-04-29 19:26:27 +01:00
Marc Zyngier
d11a327ed9 KVM: arm64: vgic-v3: Restrict SEIS workaround to known broken systems
Contrary to what df652bcf11 ("KVM: arm64: vgic-v3: Work around GICv3
locally generated SErrors") was asserting, there is at least one other
system out there (Cavium ThunderX2) implementing SEIS, and not in
an obviously broken way.

So instead of imposing the M1 workaround on an innocent bystander,
let's limit it to the two known broken Apple implementations.

Fixes: df652bcf11 ("KVM: arm64: vgic-v3: Work around GICv3 locally generated SErrors")
Reported-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220122103912.795026-1-maz@kernel.org
2022-01-22 11:38:16 +00:00
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
af22df997d KVM: arm64: Fix CPU interface MMIO compatibility detection
In order to detect whether a GICv3 CPU interface is MMIO capable,
we switch ICC_SRE_EL1.SRE to 0 and check whether it sticks.

However, this is only possible if *ALL* of the HCR_EL2 interrupt
overrides are set, and the CPU is perfectly allowed to ignore
the write to ICC_SRE_EL1 otherwise. This leads KVM to pretend
that a whole bunch of ARMv8.0 CPUs aren't MMIO-capable, and
breaks VMs that should work correctly otherwise.

Fix this by setting IMO/FMO/IMO before touching ICC_SRE_EL1,
and clear them afterwards. This allows us to reliably detect
the CPU interface capabilities.

Tested-by: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
Fixes: 9739f6ef05 ("KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility")
Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-03-24 17:26:38 +00:00
Marc Zyngier
9739f6ef05 KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility
It looks like we have broken firmware out there that wrongly advertises
a GICv2 compatibility interface, despite the CPUs not being able to deal
with it.

To work around this, check that the CPU initialising KVM is actually able
to switch to MMIO instead of system registers, and use that as a
precondition to enable GICv2 compatibility in KVM.

Note that the detection happens on a single CPU. If the firmware is
lying *and* that the CPUs are asymetric, all hope is lost anyway.

Reported-by: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Message-Id: <20210305185254.3730990-8-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-06 04:18:41 -05:00
Marc Zyngier
b9d699e269 KVM: arm64: Rename __vgic_v3_get_ich_vtr_el2() to __vgic_v3_get_gic_config()
As we are about to report a bit more information to the rest of
the kernel, rename __vgic_v3_get_ich_vtr_el2() to the more
explicit __vgic_v3_get_gic_config().

No functional change.

Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Message-Id: <20210305185254.3730990-7-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-06 04:18:41 -05:00
Marc Zyngier
cdb5e02ed1 KVM: arm64: Make kvm_skip_instr() and co private to HYP
In an effort to remove the vcpu PC manipulations from EL1 on nVHE
systems, move kvm_skip_instr() to be HYP-specific. EL1's intent
to increment PC post emulation is now signalled via a flag in the
vcpu structure.

Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-10 08:34:24 +00:00
Gustavo A. R. Silva
df561f6688 treewide: Use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-23 17:36:59 -05:00
Marc Zyngier
a394cf6e85 Merge branch 'kvm-arm64/misc-5.9' into kvmarm-master/next-WIP
Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-07-28 16:26:16 +01:00
Gavin Shan
3a949f4c93 KVM: arm64: Rename HSR to ESR
kvm/arm32 isn't supported since commit 541ad0150c ("arm: Remove
32bit KVM host support"). So HSR isn't meaningful since then. This
renames HSR to ESR accordingly. This shouldn't cause any functional
changes:

   * Rename kvm_vcpu_get_hsr() to kvm_vcpu_get_esr() to make the
     function names self-explanatory.
   * Rename variables from @hsr to @esr to make them self-explanatory.

Note that the renaming on uapi and tracepoint will cause ABI changes,
which we should avoid. Specificly, there are 4 related source files
in this regard:

   * arch/arm64/include/uapi/asm/kvm.h  (struct kvm_debug_exit_arch::hsr)
   * arch/arm64/kvm/handle_exit.c       (struct kvm_debug_exit_arch::hsr)
   * arch/arm64/kvm/trace_arm.h         (tracepoints)
   * arch/arm64/kvm/trace_handle_exit.h (tracepoints)

Signed-off-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Andrew Scull <ascull@google.com>
Link: https://lore.kernel.org/r/20200630015705.103366-1-gshan@redhat.com
2020-07-05 21:57:59 +01:00
David Brazdil
c50cb04303 KVM: arm64: Remove __hyp_text macro, use build rules instead
With nVHE code now fully separated from the rest of the kernel, the effects of
the __hyp_text macro (which had to be applied on all nVHE code) can be
achieved with build rules instead. The macro used to:
  (a) move code to .hyp.text ELF section, now done by renaming .text using
      `objcopy`, and
  (b) `notrace` and `__noscs` would negate effects of CC_FLAGS_FTRACE and
      CC_FLAGS_SCS, respectivelly, now those flags are  erased from
      KBUILD_CFLAGS (same way as in EFI stub).

Note that by removing __hyp_text from code shared with VHE, all VHE code is now
compiled into .text and without `notrace` and `__noscs`.

Use of '.pushsection .hyp.text' removed from assembly files as this is now also
covered by the build rules.

For MAINTAINERS: if needed to re-run, uses of macro were removed with the
following command. Formatting was fixed up manually.

  find arch/arm64/kvm/hyp -type f -name '*.c' -o -name '*.h' \
       -exec sed -i 's/ __hyp_text//g' {} +

Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-15-dbrazdil@google.com
2020-07-05 18:38:45 +01:00
Christoffer Dall
fc5d1f1a42 KVM: arm64: vgic-v3: Take cpu_if pointer directly instead of vcpu
If we move the used_lrs field to the version-specific cpu interface
structure, the following functions only operate on the struct
vgic_v3_cpu_if and not the full vcpu:

  __vgic_v3_save_state
  __vgic_v3_restore_state
  __vgic_v3_activate_traps
  __vgic_v3_deactivate_traps
  __vgic_v3_save_aprs
  __vgic_v3_restore_aprs

This is going to be very useful for nested virt, so move the used_lrs
field and change the prototypes and implementations of these functions to
take the cpu_if parameter directly.

No functional change.

Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-05-28 11:57:10 +01:00
Fuad Tabba
656012c731 KVM: Fix spelling in code comments
Fix spelling and typos (e.g., repeated words) in comments.

Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200401140310.29701-1-tabba@google.com
2020-05-16 15:05:01 +01:00
Marc Zyngier
9ed24f4b71 KVM: arm64: Move virt/kvm/arm to arch/arm64
Now that the 32bit KVM/arm host is a distant memory, let's move the
whole of the KVM/arm64 code into the arm64 tree.

As they said in the song: Welcome Home (Sanitarium).

Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200513104034.74741-1-maz@kernel.org
2020-05-16 15:03:59 +01:00
Vladimir Murzin
19f0ece439 arm64: KVM: Move vgic-v3 save/restore to virt/kvm/arm/hyp
So we can reuse the code under arch/arm

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-09-22 13:21:46 +02:00
Vladimir Murzin
b5525ce898 arm64: KVM: Move GIC accessors to arch_gicv3.h
Since we are going to share vgic-v3 save/restore code with ARM keep
arch specific accessors separately.

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-09-22 13:21:46 +02:00
Christoffer Dall
cf0ba18a44 KVM: arm/arm64: Get rid of exported aliases to static functions
When rewriting the assembly code to C code, it was useful to have
exported aliases or static functions so that we could keep the existing
common C code unmodified and at the same time rewrite arm64 from
assembly to C code, and later do the arm part.

Now when both are done, we really don't need this level of indirection
anymore, and it's time to save a few lines and brain cells.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-09-08 12:53:00 +02:00
Marc Zyngier
c585132840 arm64: KVM: vgic-v3: Relax synchronization when SRE==1
The GICv3 backend of the vgic is quite barrier heavy, in order
to ensure synchronization of the system registers and the
memory mapped view for a potential GICv2 guest.

But when the guest is using a GICv3 model, there is absolutely
no need to execute all these heavy barriers, and it is actually
beneficial to avoid them altogether.

This patch makes the synchonization conditional, and ensures
that we do not change the EL1 SRE settings if we do not need to.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-05-31 16:12:17 +02:00
Marc Zyngier
a057001e9e arm64: KVM: vgic-v3: Prevent the guest from messing with ICC_SRE_EL1
Both our GIC emulations are "strict", in the sense that we either
emulate a GICv2 or a GICv3, and not a GICv3 with GICv2 legacy
support.

But when running on a GICv3 host, we still allow the guest to
tinker with the ICC_SRE_EL1 register during its time slice:
it can switch SRE off, observe that it is off, and yet on the
next world switch, find the SRE bit to be set again. Not very
nice.

An obvious solution is to always trap accesses to ICC_SRE_EL1
(by clearing ICC_SRE_EL2.Enable), and to let the handler return
the programmed value on a read, or ignore the write.

That way, the guest can always observe that our GICv3 is SRE==1
only.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-05-31 16:12:17 +02:00
Christoffer Dall
fa89c77e89 KVM: arm/arm64: vgic-v3: Clear all dirty LRs
When saving the state of the list registers, it is critical to
reset them zero, as we could otherwise leave unexpected EOI
interrupts pending for virtual level interrupts.

Cc: stable@vger.kernel.org # v4.6+
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-05-31 16:12:09 +02:00
Marc Zyngier
b40c4892d1 arm64: KVM: vgic-v3: Only wipe LRs on vcpu exit
So far, we're always writing all possible LRs, setting the empty
ones with a zero value. This is obvious doing a low of work for
nothing, and we're better off clearing those we've actually
dirtied on the exit path (it is very rare to inject more than one
interrupt at a time anyway).

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-09 04:24:16 +00:00
Marc Zyngier
0d98d00b8d arm64: KVM: vgic-v3: Reset LRs at boot time
In order to let the GICv3 code be more lazy in the way it
accesses the LRs, it is necessary to start with a clean slate.

Let's reset the LRs on each CPU when the vgic is probed (which
includes a round trip to EL2...).

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-09 04:24:09 +00:00
Marc Zyngier
84e8b9c88d arm64: KVM: vgic-v3: Do not save an LR known to be empty
On exit, any empty LR will be signaled in ICH_ELRSR_EL2. Which
means that we do not have to save it, and we can just clear
its state in the in-memory copy.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-09 04:24:07 +00:00
Marc Zyngier
b4344545cf arm64: KVM: vgic-v3: Save maintenance interrupt state only if required
Next on our list of useless accesses is the maintenance interrupt
status registers (ICH_MISR_EL2, ICH_EISR_EL2).

It is pointless to save them if we haven't asked for a maintenance
interrupt the first place, which can only happen for two reasons:
- Underflow: ICH_HCR_UIE will be set,
- EOI: ICH_LR_EOI will be set.

These conditions can be checked on the in-memory copies of the regs.
Should any of these two condition be valid, we must read GICH_MISR.
We can then check for ICH_MISR_EOI, and only when set read
ICH_EISR_EL2.

This means that in most case, we don't have to save them at all.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-09 04:24:06 +00:00
Marc Zyngier
1b8e83c04e arm64: KVM: vgic-v3: Avoid accessing ICH registers
Just like on GICv2, we're a bit hammer-happy with GICv3, and access
them more often than we should.

Adopt a policy similar to what we do for GICv2, only save/restoring
the minimal set of registers. As we don't access the registers
linearly anymore (we may skip some), the convoluted accessors become
slightly simpler, and we can drop the ugly indexing macro that
tended to confuse the reviewers.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-09 04:24:04 +00:00
Marc Zyngier
13720a56ed arm64: KVM: Move kvm/hyp/hyp.h to include/asm/kvm_hyp.h
In order to be able to move code outside of kvm/hyp, we need to make
the global hyp.h file accessible from a standard location.

include/asm/kvm_hyp.h seems good enough.

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-02-29 18:34:18 +00:00
Marc Zyngier
fd451b90e7 arm64: KVM: vgic-v3: Restore ICH_APR0Rn_EL2 before ICH_APR1Rn_EL2
The GICv3 architecture spec says:

Writing to the active priority registers in any order other than
the following order will result in UNPREDICTABLE behavior:
- ICH_AP0R<n>_EL2.
- ICH_AP1R<n>_EL2.

So let's not pointlessly go against the rule...

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-02-24 17:25:58 +00:00
Marc Zyngier
3ffa75cd18 arm64: KVM: Remove weak attributes
As we've now switched to the new world switch implementation,
remove the weak attributes, as nobody is supposed to override
it anymore.

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-14 11:30:44 +00:00
Marc Zyngier
044ac37d12 arm64: KVM: Add compatibility aliases
So far, we've implemented the new world switch with a completely
different namespace, so that we could have both implementation
compiled in.

Let's take things one step further by adding weak aliases that
have the same names as the original implementation. The weak
attributes allows the new implementation to be overriden by the
old one, and everything still work.

At a later point, we'll be able to simply drop the old code, and
everything will hopefully keep working, thanks to the aliases we
have just added. This also saves us repainting all the callers.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-12-14 11:30:42 +00:00
Marc Zyngier
f68d2b1b73 arm64: KVM: Implement vgic-v3 save/restore
Implement the vgic-v3 save restore as a direct translation of
the assembly code version.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-14 11:30:39 +00:00