The ISA_EXT registers to enabled/disable ISA extensions for VCPU
are always available when underlying host has the corresponding
ISA extension. The copy_isa_ext_reg_indices() called by the
KVM_GET_REG_LIST API does not align with this expectation so
let's fix it.
Fixes: 031f9efafc ("KVM: riscv: Add KVM_GET_REG_LIST API support")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
KVM_GET_REG_LIST API will return all registers that are available to
KVM_GET/SET_ONE_REG APIs. It's very useful to identify some platform
regression issue during VM migration.
Since this API was already supported on arm64, it is straightforward
to enable it on riscv with similar code structure.
Signed-off-by: Haibo Xu <haibo1.xu@intel.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Make two nonfunctional changes to the vector get/set vector reg
functions and their supporting function for simplification and
readability. The first is to not pass KVM_REG_RISCV_VECTOR, but
rather integrate it directly into the masking. The second is to
rename reg_val to reg_addr where and address is used instead of
a value.
Also opportunistically touch up some of the code formatting for
a third nonfunctional change.
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
riscv_vcpu_set_isa_ext_single() will prevent any write of isa_ext regs
if the vcpu already started spinning.
But if there's no extension state (enabled/disabled) made by the
userspace, there's no need to -EBUSY out - we can treat the operation as
a no-op.
zicbom/zicboz_block_size, ISA config reg and mvendorid/march/mimpid
already works in a more permissive manner w.r.t userspace writes being a
no-op, so let's do the same with isa_ext writes.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Right now we do not allow any write in mvendorid/marchid/mimpid if the
vcpu already started, preventing these regs to be changed.
However, if userspace doesn't change them, an alternative is to consider
the reg write a no-op and avoid erroring out altogether. Userpace can
then be oblivious about KVM internals if no changes were intended in the
first place.
Allow the same form of 'lazy writing' that registers such as
zicbom/zicboz_block_size supports: avoid erroring out if userspace makes
no changes in mvendorid/marchid/mimpid during reg write.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
kvm_riscv_vcpu_set_reg_config() will return -EBUSY if the ISA config reg
is being written after the VCPU ran at least once.
The same restriction isn't placed in kvm_riscv_vcpu_get_reg_config(), so
there's a chance that we'll -EBUSY out on an ISA config reg write even
if the userspace intended no changes to it.
We'll allow the same form of 'lazy writing' that registers such as
zicbom/zicboz_block_size supports: avoid erroring out if userspace made
no changes to the ISA config reg.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
vcpu_set_reg_config() and vcpu_set_reg_isa_ext() is throwing an
EOPNOTSUPP error when !vcpu->arch.ran_atleast_once. In similar cases
we're throwing an EBUSY error, like in mvendorid/marchid/mimpid
set_reg().
EOPNOTSUPP has a conotation of finality. EBUSY is more adequate in this
case since its a condition/error related to the vcpu lifecycle.
Change these EOPNOTSUPP instances to EBUSY.
Suggested-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
zicbom_block_size and zicboz_block_size have a peculiar API: they can be
read via get_one_reg() but any write will return a EOPNOTSUPP.
It makes sense to return a 'not supported' error since both values can't
be changed, but as far as userspace goes they're regs that are throwing
the same EOPNOTSUPP error even if they were read beforehand via
get_one_reg(), even if the same read value is being written back.
EOPNOTSUPP is also returned even if ZICBOM/ZICBOZ aren't enabled in the
host.
Change both to work more like their counterparts in get_one_reg() and
return -ENOENT if their respective extensions aren't available. After
that, check if the userspace is written a valid value (i.e. the host
value). Throw an -EINVAL if that's not case, let it slide otherwise.
This allows both regs to be read/written by userspace in a 'lazy'
manner, as long as the userspace doesn't change the reg vals.
Suggested-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Following a similar logic as the previous patch let's minimize the EINVAL
usage in *_one_reg() APIs by using ENOENT when an extension that
implements the reg is not available.
For consistency we're also replacing an EOPNOTSUPP instance that should
be an ENOENT since it's an "extension is not available" error.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
get_one_reg() and set_one_reg() are returning EINVAL errors for almost
everything: if a reg doesn't exist, if a reg ID is malformatted, if the
associated CPU extension that implements the reg isn't present in the
host, and for set_one_reg() if the value being written is invalid.
This isn't wrong according to the existing KVM API docs (EINVAL can be
used when there's no such register) but adding more ENOENT instances
will make easier for userspace to understand what went wrong.
Existing userspaces can be affected by this error code change. We
checked a few. As of current upstream code, crosvm doesn't check for any
particular errno code when using kvm_(get|set)_one_reg(). Neither does
QEMU. rust-vmm doesn't have kvm-riscv support yet. Thus we have a good
chance of changing these error codes now while the KVM RISC-V ecosystem
is still new, minimizing user impact.
Change all get_one_reg() and set_one_reg() implementations to return
-ENOENT at all "no such register" cases.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
KVM userspaces need to be aware of the host SATP to allow them to
advertise it back to the guest OS.
Since this information is used to build the guest FDT we can't wait for
the SATP reg to be readable. We just need to read the SATP mode, thus
we can use the existing 'satp_mode' global that represents the SATP reg
with MODE set and both ASID and PPN cleared. E.g. for a 32 bit host
running with sv32 satp_mode is 0x80000000, for a 64 bit host running
sv57 satp_mode is 0xa000000000000000, and so on.
Add a new userspace virtual config register 'satp_mode' to allow
userspace to read the current SATP mode the host is using with
GET_ONE_REG API before spinning the vcpu.
'satp_mode' can't be changed via KVM, so SET_ONE_REG is allowed as long
as userspace writes the existing 'satp_mode'.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Let us sort isa extensions alphabetically in kvm_isa_ext_arr[] and
kvm_riscv_vcpu_isa_disable_allowed() so that future insertions are
more predictable.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
We extend the KVM ISA extension ONE_REG interface to allow KVM
user space to detect and enable Zicntr, Zicsr, Zifencei, and Zihpm
extensions for Guest/VM.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
We extend the KVM ISA extension ONE_REG interface to allow KVM
user space to detect and enable Zba and Zbs extensions for Guest/VM.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Currently, the ISA extension ONE_REG interface only allows enabling or
disabling one extension at a time. To improve this, we extend the ISA
extension ONE_REG interface (similar to SBI extension ONE_REG interface)
so that KVM user space can enable/disable multiple extensions in one
ioctl.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
The VCPU ONE_REG interface has grown over time and it will continue
to grow with new ISA extensions and other features. Let us move all
ONE_REG related code to its own source file so that vcpu.c only
focuses only on high-level VCPU functions.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Anup Patel