diff options
| author | Alexandru Elisei <alexandru.elisei@arm.com> | 2021-10-11 11:58:39 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2021-10-11 14:13:59 +0100 |
| commit | 5a4309762356f05df4c92629e5df15ab75c42c0d (patch) | |
| tree | 3ec41ed572b9b7dc323c45c9cd4e5b82744b7279 /arch/arm64/kvm/sys_regs.c | |
| parent | 00d5101b254b77c35a8d55fe46331b19192866f3 (diff) | |
KVM: arm64: Use get_raz_reg() for userspace reads of PMSWINC_EL0
PMSWINC_EL0 is a write-only register and was initially part of the VCPU
register state, but was later removed in commit 7a3ba3095a32 ("KVM:
arm64: Remove PMSWINC_EL0 shadow register"). To prevent regressions, the
register was kept accessible from userspace as Read-As-Zero (RAZ).
The read function that is used to handle userspace reads of this
register is get_raz_id_reg(), which, while technically correct, as it
returns 0, it is not semantically correct, as PMSWINC_EL0 is not an ID
register as the function name suggests.
Add a new function, get_raz_reg(), to use it as the accessor for
PMSWINC_EL0, as to not conflate get_raz_id_reg() to handle other types
of registers.
No functional change intended.
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211011105840.155815-3-alexandru.elisei@arm.com
Diffstat (limited to 'arch/arm64/kvm/sys_regs.c')
| -rw-r--r-- | arch/arm64/kvm/sys_regs.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 4adda8bf3168..1be827740f87 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1285,6 +1285,15 @@ static int set_raz_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, return __set_id_reg(vcpu, rd, uaddr, true); } +static int get_raz_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, + const struct kvm_one_reg *reg, void __user *uaddr) +{ + const u64 id = sys_reg_to_index(rd); + const u64 val = 0; + + return reg_to_user(uaddr, &val, id); +} + static int set_wi_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, const struct kvm_one_reg *reg, void __user *uaddr) { @@ -1647,7 +1656,7 @@ static const struct sys_reg_desc sys_reg_descs[] = { * previously (and pointlessly) advertised in the past... */ { PMU_SYS_REG(SYS_PMSWINC_EL0), - .get_user = get_raz_id_reg, .set_user = set_wi_reg, + .get_user = get_raz_reg, .set_user = set_wi_reg, .access = access_pmswinc, .reset = NULL }, { PMU_SYS_REG(SYS_PMSELR_EL0), .access = access_pmselr, .reset = reset_pmselr, .reg = PMSELR_EL0 }, |