From: Jing Zhang jingzhangos@google.com
mainline inclusion from mainline-v6.7-rc1 commit 8cfd5be88ebe3d71be1a2c52fc72a355bb924b49 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I97RDO CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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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 Signed-off-by: caijian caijian11@h-partners.com Signed-off-by: Xiang Chen chenxiang66@hisilicon.com --- 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 c1d8d8dfe1ff..15f44b84efd3 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2121,7 +2121,13 @@ 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),