[RFC 09/55] KVM: arm64: Set shadow EL1 registers for virtual EL2 execution

Christoffer Dall
2017-02-22T11:19:52Z

On Mon, Jan 09, 2017 at 01:24:05AM -0500, Jintack Lim wrote:
> From: Christoffer Dall <christoffer.dall@linaro.org>
>
> When entering virtual EL2, we need to reflect virtual EL2 register
> states to corresponding shadow EL1 registers. We can simply copy them if
> their formats are identical. Otherwise, we need to convert EL2 register
> state to EL1 register state.
>
> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
> Signed-off-by: Jintack Lim <jintack@cs.columbia.edu>
> ---
> arch/arm64/kvm/context.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++

Looking at this again, I'm not sure 'context.c' is a very meaningful
name.

> 1 file changed, 71 insertions(+)
>
> diff --git a/arch/arm64/kvm/context.c b/arch/arm64/kvm/context.c
> index acb4b1e..2e9e386 100644
> --- a/arch/arm64/kvm/context.c
> +++ b/arch/arm64/kvm/context.c
> @@ -17,6 +17,76 @@
>
> #include <linux/kvm_host.h>
> #include <asm/kvm_emulate.h>
> +#include <asm/esr.h>
> +
> +struct el1_el2_map {
> + enum vcpu_sysreg el1;
> + enum el2_regs el2;
> +};
> +
> +/*
> + * List of EL2 registers which can be directly applied to EL1 registers to
> + * emulate running EL2 in EL1. The EL1 registers here must either be trapped
> + * or paravirtualized in EL1.

This series doesn't deal with paravirtualizaion but only targets 8.3 so
we should clean up references to paravirtualization.

> + */
> +static const struct el1_el2_map el1_el2_map[] = {
> + { AMAIR_EL1, AMAIR_EL2 },
> + { MAIR_EL1, MAIR_EL2 },
> + { TTBR0_EL1, TTBR0_EL2 },
> + { ACTLR_EL1, ACTLR_EL2 },
> + { AFSR0_EL1, AFSR0_EL2 },
> + { AFSR1_EL1, AFSR1_EL2 },
> + { SCTLR_EL1, SCTLR_EL2 },
> + { VBAR_EL1, VBAR_EL2 },
> +};
> +
> +static inline u64 tcr_el2_ips_to_tcr_el1_ps(u64 tcr_el2)
> +{
> + return ((tcr_el2 & TCR_EL2_PS_MASK) >> TCR_EL2_PS_SHIFT)
> + << TCR_IPS_SHIFT;
> +}
> +
> +static inline u64 cptr_el2_to_cpacr_el1(u64 cptr_el2)
> +{
> + u64 cpacr_el1 = 0;
> +
> + if (!(cptr_el2 & CPTR_EL2_TFP))
> + cpacr_el1 |= CPACR_EL1_FPEN;
> + if (cptr_el2 & CPTR_EL2_TTA)
> + cpacr_el1 |= CPACR_EL1_TTA;
> +
> + return cpacr_el1;
> +}
> +
> +static void create_shadow_el1_sysregs(struct kvm_vcpu *vcpu)
> +{
> + u64 *s_sys_regs = vcpu->arch.ctxt.shadow_sys_regs;
> + u64 *el2_regs = vcpu->arch.ctxt.el2_regs;
> + u64 tcr_el2;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(el1_el2_map); i++) {
> + const struct el1_el2_map *map = &el1_el2_map[i];
> +
> + s_sys_regs[map->el1] = el2_regs[map->el2];
> + }
> +
> + tcr_el2 = el2_regs[TCR_EL2];
> + s_sys_regs[TCR_EL1] =
> + TCR_EPD1 | /* disable TTBR1_EL1 */
> + ((tcr_el2 & TCR_EL2_TBI) ? TCR_TBI0 : 0) |
> + tcr_el2_ips_to_tcr_el1_ps(tcr_el2) |
> + (tcr_el2 & TCR_EL2_TG0_MASK) |
> + (tcr_el2 & TCR_EL2_ORGN0_MASK) |
> + (tcr_el2 & TCR_EL2_IRGN0_MASK) |
> + (tcr_el2 & TCR_EL2_T0SZ_MASK);
> +
> + /* Rely on separate VMID for VA context, always use ASID 0 */
> + s_sys_regs[TTBR0_EL1] &= ~GENMASK_ULL(63, 48);
> + s_sys_regs[TTBR1_EL1] = 0;
> +
> + s_sys_regs[CPACR_EL1] = cptr_el2_to_cpacr_el1(el2_regs[CPTR_EL2]);
> +}
>
> /**
> * kvm_arm_setup_shadow_state -- prepare shadow state based on emulated mode
> @@ -37,6 +107,7 @@ void kvm_arm_setup_shadow_state(struct kvm_vcpu *vcpu)
> else
> ctxt->hw_pstate |= PSR_MODE_EL1t;
>
> + create_shadow_el1_sysregs(vcpu);
> ctxt->hw_sys_regs = ctxt->shadow_sys_regs;
> ctxt->hw_sp_el1 = ctxt->el2_regs[SP_EL2];
> } else {
> --
> 1.9.1
>
>