From: Jing Zhang <jingzhangos@google.com> mainline inclusion from mainline-v6.7-rc1 commit 8cfd5be88ebe3d71be1a2c52fc72a355bb924b49 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IBN3WI CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ------------------------------------------------------------------------ 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 <jingzhangos@google.com> [oliver: restrict features that are illogical to change] Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20231003230408.3405722-9-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev> --- 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 4552c02f2f8c..62618905a911 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2166,7 +2166,13 @@ 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), }, { SYS_DESC(SYS_ID_AA64PFR1_EL1), .access = access_id_reg, .get_user = get_id_reg, .set_user = set_id_aa64pfr1_el1, .reset = kvm_read_sanitised_id_reg, }, -- 2.33.0