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authorXu Lu <luxu.kernel@bytedance.com>2025-07-14 17:45:54 +0800
committerAnup Patel <anup@brainfault.org>2025-07-28 22:27:40 +0530
commit3729fe8cbb4807c6156938bc0eb643d97775a80d (patch)
tree2de95fe95aaa67cfaf8319cab4e8d6af695a2032
parent1f6d0eee54f7ed498a5e4ab3e12ea81bdac86b89 (diff)
RISC-V: KVM: Delegate illegal instruction fault to VS mode
Delegate illegal instruction fault to VS mode by default to avoid such exceptions being trapped to HS and redirected back to VS. The delegation of illegal instruction fault is particularly important to guest applications that use vector instructions frequently. In such cases, an illegal instruction fault will be raised when guest user thread uses vector instruction the first time and then guest kernel will enable user thread to execute following vector instructions. The fw pmu event counter remains undeleted so that guest can still query illegal instruction events via sbi call. Guest will only see zero count on illegal instruction faults and know 'firmware' has delegated it. Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Xu Lu <luxu.kernel@bytedance.com> Link: https://lore.kernel.org/r/20250714094554.89151-1-luxu.kernel@bytedance.com Signed-off-by: Anup Patel <anup@brainfault.org>
-rw-r--r--arch/riscv/include/asm/kvm_host.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index dae26110e9b25..d71d3299a335c 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -47,6 +47,7 @@
#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE
#define KVM_HEDELEG_DEFAULT (BIT(EXC_INST_MISALIGNED) | \
+ BIT(EXC_INST_ILLEGAL) | \
BIT(EXC_BREAKPOINT) | \
BIT(EXC_SYSCALL) | \
BIT(EXC_INST_PAGE_FAULT) | \