From 2b351e3d04be9e1533f26c3464f1e44a5beace30 Mon Sep 17 00:00:00 2001 From: Fangyu Yu Date: Thu, 21 Aug 2025 10:25:40 -0400 Subject: [PATCH] RISC-V: KVM: Write hgatp register with valid mode bits According to the RISC-V Privileged Architecture Spec, when MODE=Bare is selected,software must write zero to the remaining fields of hgatp. We have detected the valid mode supported by the HW before, So using a valid mode to detect how many vmid bits are supported. Fixes: fd7bb4a251df ("RISC-V: KVM: Implement VMID allocator") Reviewed-by: Nutty Liu Reviewed-by: Troy Mitchell Reviewed-by: Guo Ren (Alibaba DAMO Academy) Signed-off-by: Fangyu Yu Signed-off-by: Guo Ren (Alibaba DAMO Academy) Link: https://lore.kernel.org/r/20250821142542.2472079-2-guoren@kernel.org Signed-off-by: Anup Patel --- arch/riscv/kvm/vmid.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/riscv/kvm/vmid.c b/arch/riscv/kvm/vmid.c index 3b426c800480..5f33625f4070 100644 --- a/arch/riscv/kvm/vmid.c +++ b/arch/riscv/kvm/vmid.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include @@ -28,7 +29,7 @@ void __init kvm_riscv_gstage_vmid_detect(void) /* Figure-out number of VMID bits in HW */ old = csr_read(CSR_HGATP); - csr_write(CSR_HGATP, old | HGATP_VMID); + csr_write(CSR_HGATP, (kvm_riscv_gstage_mode << HGATP_MODE_SHIFT) | HGATP_VMID); vmid_bits = csr_read(CSR_HGATP); vmid_bits = (vmid_bits & HGATP_VMID) >> HGATP_VMID_SHIFT; vmid_bits = fls_long(vmid_bits); -- 2.47.3