diff options
| author | Ben Horgan <ben.horgan@arm.com> | 2026-03-13 17:45:41 +0300 |
|---|---|---|
| committer | James Morse <james.morse@arm.com> | 2026-03-27 18:27:32 +0300 |
| commit | eda1cd1f9d29b382a07d757cf8b29f9ee636355f (patch) | |
| tree | 68423cf034ac478d99be321799b69b0c341e1739 | |
| parent | 29fa1be82b83f87e603ed4c21fe86c6e05fd0282 (diff) | |
| download | linux-eda1cd1f9d29b382a07d757cf8b29f9ee636355f.tar.xz | |
KVM: arm64: Preserve host MPAM configuration when changing traps
When KVM enables or disables MPAM traps to EL2 it clears all other bits in
MPAM2_EL2. Notably, it clears the partition ids (PARTIDs) and performance
monitoring groups (PMGs). Avoid changing these bits in anticipation of
adding support for MPAM in the kernel. Otherwise, on a VHE system with the
host running at EL2 where MPAM2_EL2 and MPAM1_EL1 access the same register,
any attempt to use MPAM to monitor or partition resources for kernel space
would be foiled by running a KVM guest. Additionally, MPAM2_EL2.EnMPAMSM is
always set to 0 which causes MPAMSM_EL1 to always trap. Keep EnMPAMSM set
to 1 when not in a guest so that the kernel can use MPAMSM_EL1.
Tested-by: Gavin Shan <gshan@redhat.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Zeng Heng <zengheng4@huawei.com>
Tested-by: Punit Agrawal <punit.agrawal@oss.qualcomm.com>
Tested-by: Jesse Chick <jessechick@os.amperecomputing.com>
Reviewed-by: Zeng Heng <zengheng4@huawei.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
| -rw-r--r-- | arch/arm64/kvm/hyp/include/hyp/switch.h | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 2597e8bda867..0b50ddd530f3 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -267,7 +267,8 @@ static inline void __deactivate_traps_hfgxtr(struct kvm_vcpu *vcpu) static inline void __activate_traps_mpam(struct kvm_vcpu *vcpu) { - u64 r = MPAM2_EL2_TRAPMPAM0EL1 | MPAM2_EL2_TRAPMPAM1EL1; + u64 clr = MPAM2_EL2_EnMPAMSM; + u64 set = MPAM2_EL2_TRAPMPAM0EL1 | MPAM2_EL2_TRAPMPAM1EL1; if (!system_supports_mpam()) return; @@ -277,18 +278,21 @@ static inline void __activate_traps_mpam(struct kvm_vcpu *vcpu) write_sysreg_s(MPAMHCR_EL2_TRAP_MPAMIDR_EL1, SYS_MPAMHCR_EL2); } else { /* From v1.1 TIDR can trap MPAMIDR, set it unconditionally */ - r |= MPAM2_EL2_TIDR; + set |= MPAM2_EL2_TIDR; } - write_sysreg_s(r, SYS_MPAM2_EL2); + sysreg_clear_set_s(SYS_MPAM2_EL2, clr, set); } static inline void __deactivate_traps_mpam(void) { + u64 clr = MPAM2_EL2_TRAPMPAM0EL1 | MPAM2_EL2_TRAPMPAM1EL1 | MPAM2_EL2_TIDR; + u64 set = MPAM2_EL2_EnMPAMSM; + if (!system_supports_mpam()) return; - write_sysreg_s(0, SYS_MPAM2_EL2); + sysreg_clear_set_s(SYS_MPAM2_EL2, clr, set); if (system_supports_mpam_hcr()) write_sysreg_s(MPAMHCR_HOST_FLAGS, SYS_MPAMHCR_EL2); |