diff options
| author | Lukas Gerlach <lukas.gerlach@cispa.de> | 2026-03-03 15:19:43 +0100 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2026-03-06 11:20:30 +0530 |
| commit | 8f0c15c4b14f27dd9bd35971adb9c908241f2f63 (patch) | |
| tree | 15bb61e93fd090c96e917946b793a78e562b1c41 | |
| parent | ec87a82ca8740891bce9e93e79ea2cd6c2d70ac8 (diff) | |
KVM: riscv: Fix Spectre-v1 in floating-point register access
User-controlled indices are used to index into floating-point registers.
Sanitize them with array_index_nospec() to prevent speculative
out-of-bounds access.
Reviewed-by: Radim Krčmář <radim.krcmar@oss.qualcomm.com>
Signed-off-by: Lukas Gerlach <lukas.gerlach@cispa.de>
Link: https://lore.kernel.org/r/20260303-kvm-riscv-spectre-v1-v2-3-192caab8e0dc@cispa.de
Signed-off-by: Anup Patel <anup@brainfault.org>
| -rw-r--r-- | arch/riscv/kvm/vcpu_fp.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/arch/riscv/kvm/vcpu_fp.c b/arch/riscv/kvm/vcpu_fp.c index 030904d82b58..bd5a9e7e7165 100644 --- a/arch/riscv/kvm/vcpu_fp.c +++ b/arch/riscv/kvm/vcpu_fp.c @@ -10,6 +10,7 @@ #include <linux/errno.h> #include <linux/err.h> #include <linux/kvm_host.h> +#include <linux/nospec.h> #include <linux/uaccess.h> #include <asm/cpufeature.h> @@ -93,9 +94,11 @@ int kvm_riscv_vcpu_get_reg_fp(struct kvm_vcpu *vcpu, if (reg_num == KVM_REG_RISCV_FP_F_REG(fcsr)) reg_val = &cntx->fp.f.fcsr; else if ((KVM_REG_RISCV_FP_F_REG(f[0]) <= reg_num) && - reg_num <= KVM_REG_RISCV_FP_F_REG(f[31])) + reg_num <= KVM_REG_RISCV_FP_F_REG(f[31])) { + reg_num = array_index_nospec(reg_num, + ARRAY_SIZE(cntx->fp.f.f)); reg_val = &cntx->fp.f.f[reg_num]; - else + } else return -ENOENT; } else if ((rtype == KVM_REG_RISCV_FP_D) && riscv_isa_extension_available(vcpu->arch.isa, d)) { @@ -107,6 +110,8 @@ int kvm_riscv_vcpu_get_reg_fp(struct kvm_vcpu *vcpu, reg_num <= KVM_REG_RISCV_FP_D_REG(f[31])) { if (KVM_REG_SIZE(reg->id) != sizeof(u64)) return -EINVAL; + reg_num = array_index_nospec(reg_num, + ARRAY_SIZE(cntx->fp.d.f)); reg_val = &cntx->fp.d.f[reg_num]; } else return -ENOENT; @@ -138,9 +143,11 @@ int kvm_riscv_vcpu_set_reg_fp(struct kvm_vcpu *vcpu, if (reg_num == KVM_REG_RISCV_FP_F_REG(fcsr)) reg_val = &cntx->fp.f.fcsr; else if ((KVM_REG_RISCV_FP_F_REG(f[0]) <= reg_num) && - reg_num <= KVM_REG_RISCV_FP_F_REG(f[31])) + reg_num <= KVM_REG_RISCV_FP_F_REG(f[31])) { + reg_num = array_index_nospec(reg_num, + ARRAY_SIZE(cntx->fp.f.f)); reg_val = &cntx->fp.f.f[reg_num]; - else + } else return -ENOENT; } else if ((rtype == KVM_REG_RISCV_FP_D) && riscv_isa_extension_available(vcpu->arch.isa, d)) { @@ -152,6 +159,8 @@ int kvm_riscv_vcpu_set_reg_fp(struct kvm_vcpu *vcpu, reg_num <= KVM_REG_RISCV_FP_D_REG(f[31])) { if (KVM_REG_SIZE(reg->id) != sizeof(u64)) return -EINVAL; + reg_num = array_index_nospec(reg_num, + ARRAY_SIZE(cntx->fp.d.f)); reg_val = &cntx->fp.d.f[reg_num]; } else return -ENOENT; |