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RISC-V: KVM: Remove scounteren initialization

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Scounteren CSR controls the direct access the hpmcounters and cycle/
instret/time from the userspace. It's the supervisor's responsibility
to set it up correctly for it's user space. They hypervisor doesn't
need to decide the policy on behalf of the supervisor.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20250515-fix_scounteren_vs-v3-1-729dc088943e@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Atish Patra 2025-05-15 16:11:18 -07:00 committed by Anup Patel
parent 9f0e6b98c1
commit 5bc4097867
2 changed files with 10 additions and 3 deletions
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10
arch/riscv/kernel/head.S
View File

@ -131,6 +131,12 @@ secondary_start_sbi:
csrw CSR_IE, zero
csrw CSR_IP, zero
#ifndef CONFIG_RISCV_M_MODE
/* Enable time CSR */
li t0, 0x2
csrw CSR_SCOUNTEREN, t0
#endif
/* Load the global pointer */
load_global_pointer
@ -226,6 +232,10 @@ SYM_CODE_START(_start_kernel)
* to hand it to us.
*/
csrr a0, CSR_MHARTID
#else
/* Enable time CSR */
li t0, 0x2
csrw CSR_SCOUNTEREN, t0
#endif /* CONFIG_RISCV_M_MODE */
/* Load the global pointer */

3
arch/riscv/kvm/vcpu.c
View File

@ -79,9 +79,6 @@ static void kvm_riscv_vcpu_context_reset(struct kvm_vcpu *vcpu)
cntx->hstatus |= HSTATUS_VTW;
cntx->hstatus |= HSTATUS_SPVP;
cntx->hstatus |= HSTATUS_SPV;
/* By default, make CY, TM, and IR counters accessible in VU mode */
csr->scounteren = 0x7;
}
static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu)