From 8cfd5be88ebe3d71be1a2c52fc72a355bb924b49 Mon Sep 17 00:00:00 2001 From: Jing Zhang Date: Tue, 3 Oct 2023 23:04:04 +0000 Subject: [PATCH] KVM: arm64: Allow userspace to change ID_AA64PFR0_EL1 Allow userspace to change the guest-visible value of the register with some severe limitation: - No changes to features not virtualized by KVM (AMU, MPAM, RAS) - Short of full GICv2 emulation in kernel, hiding GICv3 from the guest makes absolutely no sense. - FP is effectively assumed for KVM VMs. Signed-off-by: Jing Zhang [oliver: restrict features that are illogical to change] Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20231003230408.3405722-9-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index d850b05eb5042..dbf915f88b17b 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2057,7 +2057,13 @@ static const struct sys_reg_desc sys_reg_descs[] = { .get_user = get_id_reg, .set_user = set_id_reg, .reset = read_sanitised_id_aa64pfr0_el1, - .val = ID_AA64PFR0_EL1_CSV2_MASK | ID_AA64PFR0_EL1_CSV3_MASK, }, + .val = ~(ID_AA64PFR0_EL1_AMU | + ID_AA64PFR0_EL1_MPAM | + ID_AA64PFR0_EL1_SVE | + ID_AA64PFR0_EL1_RAS | + ID_AA64PFR0_EL1_GIC | + ID_AA64PFR0_EL1_AdvSIMD | + ID_AA64PFR0_EL1_FP), }, ID_SANITISED(ID_AA64PFR1_EL1), ID_UNALLOCATED(4,2), ID_UNALLOCATED(4,3), -- 2.30.2