Re: [PATCH v2 06/45] KVM: arm64: Make MPAMSM_EL1 accesses UNDEF
From: Jonathan Cameron <jonathan.cameron@huawei.com>
Date: 2026-01-05 16:47:44
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kvmarm, lkml
On Fri, 19 Dec 2025 18:11:08 +0000 Ben Horgan [off-list ref] wrote:
The MPAMSM_EL1 controls the MPAM labeling for an SMCU, Streaming Mode Compute Unit. As there is on MPAM support in kvm, make sure MPAMSM_EL1 accesses trigger an UNDEF. The range of valid configurations for the PARTID and PMG in MPAMSM_EL1 is not currently specified in Arm Architectural Reference Manual but the architect has confirmed that it is intended to be the same as that for the cpu configuration in the MPAMy_ELx registers.
Good to know but I'm not seeing why it matters in this patch. Perhaps a little more on that?
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
quoted hunk ↗ jump to hunk
--- arch/arm64/kvm/sys_regs.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index c8fd7c6a12a1..72654ab984ee 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c@@ -3373,6 +3373,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { { SYS_DESC(SYS_MPAM1_EL1), undef_access }, { SYS_DESC(SYS_MPAM0_EL1), undef_access }, + { SYS_DESC(SYS_MPAMSM_EL1), undef_access }, + { SYS_DESC(SYS_VBAR_EL1), access_rw, reset_val, VBAR_EL1, 0 }, { SYS_DESC(SYS_DISR_EL1), NULL, reset_val, DISR_EL1, 0 },