riscv: Rearrange hwcap.h and cpufeature.h

Now hwcap.h and cpufeature.h are mutually including each other, and most of
the variable/API declarations in hwcap.h are implemented in cpufeature.c,
so, it's better to move them into cpufeature.h and leave only macros for
ISA extension logical IDs in hwcap.h.

BTW, the riscv_isa_extension_mask macro is not used now, so this patch
removes it.

Suggested-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20231031064553.2319688-2-xiao.w.wang@intel.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

RISC-V: KVM: return ENOENT in *_one_reg() when reg is unknown

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>

RISC-V: KVM: Improve ISA extension by using a bitmap

Currently, the every vcpu only stores the ISA extensions in a unsigned long
which is not scalable as number of extensions will continue to grow.
Using a bitmap allows the ISA extension to support any number of
extensions. The CONFIG one reg interface implementation is modified to
support the bitmap as well. But it is meant only for base extensions.
Thus, the first element of the bitmap array is sufficient for that
interface.

In the future, all the new multi-letter extensions must use the
ISA_EXT one reg interface that allows enabling/disabling any extension
now.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>

RISC-V: KVM: include missing hwcap.h into vcpu_fp

vcpu_fp uses the riscv_isa_extension mechanism which gets
defined in hwcap.h but doesn't include that head file.

While it seems to work in most cases, in certain conditions
this can lead to build failures like

../arch/riscv/kvm/vcpu_fp.c: In function ‘kvm_riscv_vcpu_fp_reset’:
../arch/riscv/kvm/vcpu_fp.c:22:13: error: implicit declaration of function ‘riscv_isa_extension_available’ [-Werror=implicit-function-declaration]
22 | if (riscv_isa_extension_available(&isa, f) ||
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../arch/riscv/kvm/vcpu_fp.c:22:49: error: ‘f’ undeclared (first use in this function)
22 | if (riscv_isa_extension_available(&isa, f) ||

Fix this by simply including the necessary header.

Fixes: 0a86512dc113 ("RISC-V: KVM: Factor-out FP virtualization into separate
sources")
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Anup Patel <anup@brainfault.org>

RISC-V: KVM: make kvm_riscv_vcpu_fp_clean() static

There are no users outside vcpu_fp.c so make kvm_riscv_vcpu_fp_clean()
static.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Anup Patel <anup.patel@wdc.com>

RISC-V: KVM: Factor-out FP virtualization into separate sources

The timer and SBI virtualization is already in separate sources.
In future, we will have vector and AIA virtualization also added
as separate sources.

To align with above described modularity, we factor-out FP
virtualization into separate sources.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Message-Id: <20211026170136.2147619-3-anup.patel@wdc.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>