From d5a32b60dc184cc7309f83648a368b94d91c797f Mon Sep 17 00:00:00 2001
From: Jing Zhang <jingzhangos@google.com>
Date: Tue, 3 Oct 2023 23:04:03 +0000
Subject: [PATCH] KVM: arm64: Allow userspace to change ID_AA64MMFR{0-2}_EL1
Allow userspace to modify the guest-visible values of these ID
registers. Prevent changes to any of the virtualization features until
KVM picks up support for nested and we have a handle on managing NV
features.
Signed-off-by: Jing Zhang <jingzhangos@google.com>
[oliver: prevent changes to EL2 features for now]
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-8-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
arch/arm64/kvm/sys_regs.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 5d1a94af42f27..d850b05eb5042 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2099,9 +2099,23 @@ static const struct sys_reg_desc sys_reg_descs[] = {
ID_UNALLOCATED(6,7),
/* CRm=7 */
- ID_SANITISED(ID_AA64MMFR0_EL1),
- ID_SANITISED(ID_AA64MMFR1_EL1),
- ID_SANITISED(ID_AA64MMFR2_EL1),
+ ID_WRITABLE(ID_AA64MMFR0_EL1, ~(ID_AA64MMFR0_EL1_RES0 |
+ ID_AA64MMFR0_EL1_TGRAN4_2 |
+ ID_AA64MMFR0_EL1_TGRAN64_2 |
+ ID_AA64MMFR0_EL1_TGRAN16_2)),
+ ID_WRITABLE(ID_AA64MMFR1_EL1, ~(ID_AA64MMFR1_EL1_RES0 |
+ ID_AA64MMFR1_EL1_HCX |
+ ID_AA64MMFR1_EL1_XNX |
+ ID_AA64MMFR1_EL1_TWED |
+ ID_AA64MMFR1_EL1_XNX |
+ ID_AA64MMFR1_EL1_VH |
+ ID_AA64MMFR1_EL1_VMIDBits)),
+ ID_WRITABLE(ID_AA64MMFR2_EL1, ~(ID_AA64MMFR2_EL1_RES0 |
+ ID_AA64MMFR2_EL1_EVT |
+ ID_AA64MMFR2_EL1_FWB |
+ ID_AA64MMFR2_EL1_IDS |
+ ID_AA64MMFR2_EL1_NV |
+ ID_AA64MMFR2_EL1_CCIDX)),
ID_SANITISED(ID_AA64MMFR3_EL1),
ID_UNALLOCATED(7,4),
ID_UNALLOCATED(7,5),
--
2.30.2