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| author | Marc Zyngier <maz@kernel.org> | 2023-02-09 17:58:17 +0000 |
|---|---|---|
| committer | Oliver Upton <oliver.upton@linux.dev> | 2023-02-11 10:13:29 +0000 |
| commit | e6b367db0f9192692a3f3057878f1259fe966d33 (patch) | |
| tree | 243a7c2e9d72fca95eea58571cb9b25fd062c4c3 | |
| parent | d9552fe133f9f7c357460b041e2d3b20310adf8d (diff) | |
| download | lwn-e6b367db0f9192692a3f3057878f1259fe966d33.tar.gz lwn-e6b367db0f9192692a3f3057878f1259fe966d33.zip | |
KVM: arm64: nv: Allow a sysreg to be hidden from userspace only
So far, we never needed to distinguish between registers hidden
from userspace and being hidden from a guest (they are always
either visible to both, or hidden from both).
With NV, we have the ugly case of the EL02 and EL12 registers,
which are only a view on the EL0 and EL1 registers. It makes
absolutely no sense to expose them to userspace, since it
already has the canonical view.
Add a new visibility flag (REG_HIDDEN_USER) and a new helper that
checks for it and REG_HIDDEN when checking whether to expose
a sysreg to userspace. Subsequent patches will make use of it.
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230209175820.1939006-16-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
| -rw-r--r-- | arch/arm64/kvm/sys_regs.c | 6 | ||||
| -rw-r--r-- | arch/arm64/kvm/sys_regs.h | 14 |
2 files changed, 15 insertions, 5 deletions
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index de209059fd34..55a14c86a455 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2980,7 +2980,7 @@ int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg, int ret; r = id_to_sys_reg_desc(vcpu, reg->id, table, num); - if (!r) + if (!r || sysreg_hidden_user(vcpu, r)) return -ENOENT; if (r->get_user) { @@ -3024,7 +3024,7 @@ int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg, return -EFAULT; r = id_to_sys_reg_desc(vcpu, reg->id, table, num); - if (!r) + if (!r || sysreg_hidden_user(vcpu, r)) return -ENOENT; if (sysreg_user_write_ignore(vcpu, r)) @@ -3118,7 +3118,7 @@ static int walk_one_sys_reg(const struct kvm_vcpu *vcpu, if (!(rd->reg || rd->get_user)) return 0; - if (sysreg_hidden(vcpu, rd)) + if (sysreg_hidden_user(vcpu, rd)) return 0; if (!copy_reg_to_user(rd, uind)) diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h index e4ebb3a379fd..6b11f2cc7146 100644 --- a/arch/arm64/kvm/sys_regs.h +++ b/arch/arm64/kvm/sys_regs.h @@ -85,8 +85,9 @@ struct sys_reg_desc { }; #define REG_HIDDEN (1 << 0) /* hidden from userspace and guest */ -#define REG_RAZ (1 << 1) /* RAZ from userspace and guest */ -#define REG_USER_WI (1 << 2) /* WI from userspace only */ +#define REG_HIDDEN_USER (1 << 1) /* hidden from userspace only */ +#define REG_RAZ (1 << 2) /* RAZ from userspace and guest */ +#define REG_USER_WI (1 << 3) /* WI from userspace only */ static __printf(2, 3) inline void print_sys_reg_msg(const struct sys_reg_params *p, @@ -152,6 +153,15 @@ static inline bool sysreg_hidden(const struct kvm_vcpu *vcpu, return sysreg_visibility(vcpu, r) & REG_HIDDEN; } +static inline bool sysreg_hidden_user(const struct kvm_vcpu *vcpu, + const struct sys_reg_desc *r) +{ + if (likely(!r->visibility)) + return false; + + return r->visibility(vcpu, r) & (REG_HIDDEN | REG_HIDDEN_USER); +} + static inline bool sysreg_visible_as_raz(const struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) { |