[PATCH 4/5] KVM: arm64: Do not let a L1 hypervisor access the *32_EL2 sysregs

Marc Zyngier
2023-10-23T09:55:30Z

DBGVCR32_EL2, DACR32_EL2, IFSR32_EL2 and FPEXC32_EL2 are required to
UNDEF when AArch32 isn't implemented, which is definitely the case when
running NV.

Given that this is the only case where these registers can trap,
unconditionally inject an UNDEF exception.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20231013223311.3950585-1-maz@kernel.org
---
arch/arm64/kvm/sys_regs.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0afd6136e275..0071ccccaf00 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1961,7 +1961,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
// DBGDTR[TR]X_EL0 share the same encoding
{ SYS_DESC(SYS_DBGDTRTX_EL0), trap_raz_wi },

- { SYS_DESC(SYS_DBGVCR32_EL2), NULL, reset_val, DBGVCR32_EL2, 0 },
+ { SYS_DESC(SYS_DBGVCR32_EL2), trap_undef, reset_val, DBGVCR32_EL2, 0 },

{ SYS_DESC(SYS_MPIDR_EL1), NULL, reset_mpidr, MPIDR_EL1 },

@@ -2380,18 +2380,18 @@ static const struct sys_reg_desc sys_reg_descs[] = {
EL2_REG(VTTBR_EL2, access_rw, reset_val, 0),
EL2_REG(VTCR_EL2, access_rw, reset_val, 0),

- { SYS_DESC(SYS_DACR32_EL2), NULL, reset_unknown, DACR32_EL2 },
+ { SYS_DESC(SYS_DACR32_EL2), trap_undef, reset_unknown, DACR32_EL2 },
EL2_REG(HDFGRTR_EL2, access_rw, reset_val, 0),
EL2_REG(HDFGWTR_EL2, access_rw, reset_val, 0),
EL2_REG(SPSR_EL2, access_rw, reset_val, 0),
EL2_REG(ELR_EL2, access_rw, reset_val, 0),
{ SYS_DESC(SYS_SP_EL1), access_sp_el1},

- { SYS_DESC(SYS_IFSR32_EL2), NULL, reset_unknown, IFSR32_EL2 },
+ { SYS_DESC(SYS_IFSR32_EL2), trap_undef, reset_unknown, IFSR32_EL2 },
EL2_REG(AFSR0_EL2, access_rw, reset_val, 0),
EL2_REG(AFSR1_EL2, access_rw, reset_val, 0),
EL2_REG(ESR_EL2, access_rw, reset_val, 0),
- { SYS_DESC(SYS_FPEXC32_EL2), NULL, reset_val, FPEXC32_EL2, 0x700 },
+ { SYS_DESC(SYS_FPEXC32_EL2), trap_undef, reset_val, FPEXC32_EL2, 0x700 },

EL2_REG(FAR_EL2, access_rw, reset_val, 0),
EL2_REG(HPFAR_EL2, access_rw, reset_val, 0),
--
2.39.2