From ec87a82ca8740891bce9e93e79ea2cd6c2d70ac8 Mon Sep 17 00:00:00 2001 From: Lukas Gerlach Date: Tue, 3 Mar 2026 15:19:42 +0100 Subject: [PATCH] KVM: riscv: Fix Spectre-v1 in AIA CSR access MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit User-controlled indices are used to access AIA CSR registers. Sanitize them with array_index_nospec() to prevent speculative out-of-bounds access. Similar to x86 commit 8c86405f606c ("KVM: x86: Protect ioapic_read_indirect() from Spectre-v1/L1TF attacks") and arm64 commit 41b87599c743 ("KVM: arm/arm64: vgic: fix possible spectre-v1 in vgic_get_irq()"). Reviewed-by: Radim Krčmář Signed-off-by: Lukas Gerlach Link: https://lore.kernel.org/r/20260303-kvm-riscv-spectre-v1-v2-2-192caab8e0dc@cispa.de Signed-off-by: Anup Patel --- arch/riscv/kvm/aia.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kvm/aia.c b/arch/riscv/kvm/aia.c index cac3c2b51d72..38de97d2f5b8 100644 --- a/arch/riscv/kvm/aia.c +++ b/arch/riscv/kvm/aia.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -182,10 +183,13 @@ int kvm_riscv_vcpu_aia_get_csr(struct kvm_vcpu *vcpu, unsigned long *out_val) { struct kvm_vcpu_aia_csr *csr = &vcpu->arch.aia_context.guest_csr; + unsigned long regs_max = sizeof(struct kvm_riscv_aia_csr) / sizeof(unsigned long); - if (reg_num >= sizeof(struct kvm_riscv_aia_csr) / sizeof(unsigned long)) + if (reg_num >= regs_max) return -ENOENT; + reg_num = array_index_nospec(reg_num, regs_max); + *out_val = 0; if (kvm_riscv_aia_available()) *out_val = ((unsigned long *)csr)[reg_num]; @@ -198,10 +202,13 @@ int kvm_riscv_vcpu_aia_set_csr(struct kvm_vcpu *vcpu, unsigned long val) { struct kvm_vcpu_aia_csr *csr = &vcpu->arch.aia_context.guest_csr; + unsigned long regs_max = sizeof(struct kvm_riscv_aia_csr) / sizeof(unsigned long); - if (reg_num >= sizeof(struct kvm_riscv_aia_csr) / sizeof(unsigned long)) + if (reg_num >= regs_max) return -ENOENT; + reg_num = array_index_nospec(reg_num, regs_max); + if (kvm_riscv_aia_available()) { ((unsigned long *)csr)[reg_num] = val;