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Message-ID: <20250106154847.1100344-1-cleger@rivosinc.com>
Date: Mon, 6 Jan 2025 16:48:37 +0100
From: Clément Léger <cleger@...osinc.com>
To: Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Anup Patel <anup@...infault.org>,
Atish Patra <atishp@...shpatra.org>,
linux-riscv@...ts.infradead.org,
linux-kernel@...r.kernel.org,
kvm@...r.kernel.org,
kvm-riscv@...ts.infradead.org
Cc: Clément Léger <cleger@...osinc.com>
Subject: [PATCH 0/6] riscv: add SBI FWFT misaligned exception delegation support
The SBI Firmware Feature extension allows the S-mode to request some
specific features (either hardware or software) to be enabled. This
series uses this extension to request misaligned access exception
delegation to S-mode in order to let the kernel handle it. It also adds
support for the KVM FWFT SBI extension based on the misaligned access
handling infrastructure.
FWFT SBI extension is part of the SBI V3.0 specifications [1]. It can be
tested using the qemu provided at [2] which contains the series from
[3]. kvm-unit-tests [4] can be used inside kvm to tests the correct
delegation of misaligned exceptions. Upstream OpenSBI can be used.
The test can be run using a small utility[5] as well as using kvm-tools:
$ qemu-system-riscv64 \
-cpu rv64,trap-misaligned-access=true,v=true \
-M virt \
-m 1024M \
-bios fw_dynamic.bin \
-kernel Image
...
# ./unaligned
Buf base address: 0x5555756ff0f0
Testing emulated misaligned accesses, size 2, offset 1
Testing non-emulated misaligned accesses, size 2, offset 1
Testing emulated misaligned accesses, size 4, offset 1
Testing non-emulated misaligned accesses, size 4, offset 1
Testing emulated misaligned accesses, size 4, offset 2
Testing non-emulated misaligned accesses, size 4, offset 2
Testing emulated misaligned accesses, size 4, offset 3
Testing non-emulated misaligned accesses, size 4, offset 3
Testing emulated misaligned accesses, size 8, offset 1
Testing non-emulated misaligned accesses, size 8, offset 1
Testing emulated misaligned accesses, size 8, offset 2
Testing non-emulated misaligned accesses, size 8, offset 2
Testing emulated misaligned accesses, size 8, offset 3
Testing non-emulated misaligned accesses, size 8, offset 3
Testing emulated misaligned accesses, size 8, offset 4
Testing non-emulated misaligned accesses, size 8, offset 4
Testing emulated misaligned accesses, size 8, offset 5
Testing non-emulated misaligned accesses, size 8, offset 5
Testing emulated misaligned accesses, size 8, offset 6
Testing non-emulated misaligned accesses, size 8, offset 6
Testing emulated misaligned accesses, size 8, offset 7
Testing non-emulated misaligned accesses, size 8, offset 7
# lkvm run -k sbi.flat -m 128
Info: # lkvm run -k sbi.flat -m 128 -c 1 --name guest-97
Info: Removed ghost socket file "/root/.lkvm//guest-97.sock".
##########################################################################
# kvm-unit-tests
##########################################################################
... [test messages elided]
PASS: sbi: fwft: FWFT extension probing no error
PASS: sbi: fwft: get/set reserved feature 0x6 error == SBI_ERR_DENIED
PASS: sbi: fwft: get/set reserved feature 0x3fffffff error == SBI_ERR_DENIED
PASS: sbi: fwft: get/set reserved feature 0x80000000 error == SBI_ERR_DENIED
PASS: sbi: fwft: get/set reserved feature 0xbfffffff error == SBI_ERR_DENIED
PASS: sbi: fwft: misaligned_deleg: Get misaligned deleg feature no error
PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature invalid value error
PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature invalid value error
PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value no error
PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value 0
PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value no error
PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value 1
PASS: sbi: fwft: misaligned_deleg: Verify misaligned load exception trap in supervisor
SUMMARY: 50 tests, 2 unexpected failures, 12 skipped
This series is available at [6].
Link: https://github.com/riscv-non-isa/riscv-sbi-doc/releases/download/vv3.0-rc2/riscv-sbi.pdf [1]
Link: https://github.com/rivosinc/qemu/tree/dev/cleger/misaligned [2]
Link: https://lore.kernel.org/all/20241211211933.198792-3-fkonrad@amd.com/T/ [3]
Link: https://github.com/clementleger/kvm-unit-tests/tree/dev/cleger/fwft_v1 [4]
Link: https://github.com/clementleger/unaligned_test [5]
Link: https://github.com/rivosinc/linux/tree/dev/cleger/fwft_v1 [6]
---
Clément Léger (6):
riscv: add Firmware Feature (FWFT) SBI extensions definitions
riscv: request misaligned exception delegation from SBI
RISC-V: KVM: add SBI extension init()/deinit() functions
RISC-V: KVM: add support for FWFT SBI extension
riscv: export unaligned_ctl_available() as a GPL symbol
RISC-V: KVM: add support for SBI_FWFT_MISALIGNED_DELEG
arch/riscv/include/asm/cpufeature.h | 1 +
arch/riscv/include/asm/kvm_host.h | 4 +
arch/riscv/include/asm/kvm_vcpu_sbi.h | 10 +
arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h | 37 ++++
arch/riscv/include/asm/sbi.h | 28 +++
arch/riscv/include/uapi/asm/kvm.h | 1 +
arch/riscv/kernel/traps_misaligned.c | 61 ++++++
arch/riscv/kernel/unaligned_access_speed.c | 2 +
arch/riscv/kvm/Makefile | 1 +
arch/riscv/kvm/vcpu.c | 5 +
arch/riscv/kvm/vcpu_sbi.c | 35 +++-
arch/riscv/kvm/vcpu_sbi_fwft.c | 215 +++++++++++++++++++++
12 files changed, 399 insertions(+), 1 deletion(-)
create mode 100644 arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h
create mode 100644 arch/riscv/kvm/vcpu_sbi_fwft.c
--
2.47.1
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