On Tue, 23 Nov 2021 21:01:06 +0000,
Oliver Upton <oupton@xxxxxxxxxx> wrote:
>
> Allow writes to OSLAR and forward the OSLK bit to OSLSR. Do nothing with
> the value for now.
>
> Reviewed-by: Reiji Watanabe <reijiw@xxxxxxxxxx>
> Signed-off-by: Oliver Upton <oupton@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/sysreg.h | 6 ++++++
> arch/arm64/kvm/sys_regs.c | 33 ++++++++++++++++++++++++++-------
> 2 files changed, 32 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index 16b3f1a1d468..9fad61a82047 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -129,7 +129,13 @@
> #define SYS_DBGWCRn_EL1(n) sys_reg(2, 0, 0, n, 7)
> #define SYS_MDRAR_EL1 sys_reg(2, 0, 1, 0, 0)
> #define SYS_OSLAR_EL1 sys_reg(2, 0, 1, 0, 4)
> +
> +#define SYS_OSLAR_OSLK BIT(0)
> +
> #define SYS_OSLSR_EL1 sys_reg(2, 0, 1, 1, 4)
> +
> +#define SYS_OSLSR_OSLK BIT(1)
> +
> #define SYS_OSDLR_EL1 sys_reg(2, 0, 1, 3, 4)
> #define SYS_DBGPRCR_EL1 sys_reg(2, 0, 1, 4, 4)
> #define SYS_DBGCLAIMSET_EL1 sys_reg(2, 0, 7, 8, 6)
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 7bf350b3d9cd..5dbdb45d6d44 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -44,6 +44,10 @@
> * 64bit interface.
> */
>
> +static int reg_from_user(u64 *val, const void __user *uaddr, u64 id);
> +static int reg_to_user(void __user *uaddr, const u64 *val, u64 id);
> +static u64 sys_reg_to_index(const struct sys_reg_desc *reg);
> +
> static bool read_from_write_only(struct kvm_vcpu *vcpu,
> struct sys_reg_params *params,
> const struct sys_reg_desc *r)
> @@ -287,6 +291,24 @@ static bool trap_loregion(struct kvm_vcpu *vcpu,
> return trap_raz_wi(vcpu, p, r);
> }
>
> +static bool trap_oslar_el1(struct kvm_vcpu *vcpu,
> + struct sys_reg_params *p,
> + const struct sys_reg_desc *r)
> +{
> + u64 oslsr;
> +
> + if (!p->is_write)
> + return read_from_write_only(vcpu, p, r);
> +
> + /* Forward the OSLK bit to OSLSR */
> + oslsr = __vcpu_sys_reg(vcpu, OSLSR_EL1) & ~SYS_OSLSR_OSLK;
> + if (p->regval & SYS_OSLAR_OSLK)
> + oslsr |= SYS_OSLSR_OSLK;
> +
> + __vcpu_sys_reg(vcpu, OSLSR_EL1) = oslsr;
> + return true;
> +}
> +
> static bool trap_oslsr_el1(struct kvm_vcpu *vcpu,
> struct sys_reg_params *p,
> const struct sys_reg_desc *r)
> @@ -309,9 +331,10 @@ static int set_oslsr_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> if (err)
> return err;
>
> - if (val != rd->val)
> + if ((val & ~SYS_OSLSR_OSLK) != rd->val)
> return -EINVAL;
This looks odd. It means that once I have set the lock from userspace,
I can't clear it?
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
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