Re: [PATCH v3 11/23] arm64: KVM: VHE: Split save/restore of registers shared between guest and host

Christoffer Dall
2016-02-04T19:15:09Z

On Wed, Feb 03, 2016 at 06:00:04PM +0000, Marc Zyngier wrote:
> A handful of system registers are still shared between host and guest,
> even while using VHE (tpidr*_el[01] and actlr_el1).
>
> Also, some of the vcpu state (sp_el0, PC and PSTATE) must be
> save/restored on entry/exit, as they are used on the host as well.
>
> In order to facilitate the introduction of a VHE-specific sysreg
> save/restore, make move the access to these registers to their
> own save/restore functions.
>
> No functionnal change.

uber nit: s/functionnal/functional/

>
> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> arch/arm64/kvm/hyp/sysreg-sr.c | 48 +++++++++++++++++++++++++++++-------------
> 1 file changed, 33 insertions(+), 15 deletions(-)
>
> diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
> index bd5b543..61bad17 100644
> --- a/arch/arm64/kvm/hyp/sysreg-sr.c
> +++ b/arch/arm64/kvm/hyp/sysreg-sr.c
> @@ -23,13 +23,29 @@
>
> #include "hyp.h"
>
> -/* ctxt is already in the HYP VA space */
> +/*
> + * Non-VHE: Both host and guest must save everything.
> + *
> + * VHE: Host must save tpidr*_el[01], actlr_el1, sp0, pc, pstate, and
> + * guest must save everything.
> + */
> +
> +static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
> +{
> + ctxt->sys_regs[ACTLR_EL1] = read_sysreg(actlr_el1);
> + ctxt->sys_regs[TPIDR_EL0] = read_sysreg(tpidr_el0);
> + ctxt->sys_regs[TPIDRRO_EL0] = read_sysreg(tpidrro_el0);
> + ctxt->sys_regs[TPIDR_EL1] = read_sysreg(tpidr_el1);
> + ctxt->gp_regs.regs.sp = read_sysreg(sp_el0);
> + ctxt->gp_regs.regs.pc = read_sysreg(elr_el2);
> + ctxt->gp_regs.regs.pstate = read_sysreg(spsr_el2);
> +}
> +
> static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
> {
> ctxt->sys_regs[MPIDR_EL1] = read_sysreg(vmpidr_el2);
> ctxt->sys_regs[CSSELR_EL1] = read_sysreg(csselr_el1);
> ctxt->sys_regs[SCTLR_EL1] = read_sysreg(sctlr_el1);
> - ctxt->sys_regs[ACTLR_EL1] = read_sysreg(actlr_el1);
> ctxt->sys_regs[CPACR_EL1] = read_sysreg(cpacr_el1);
> ctxt->sys_regs[TTBR0_EL1] = read_sysreg(ttbr0_el1);
> ctxt->sys_regs[TTBR1_EL1] = read_sysreg(ttbr1_el1);
> @@ -41,17 +57,11 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
> ctxt->sys_regs[MAIR_EL1] = read_sysreg(mair_el1);
> ctxt->sys_regs[VBAR_EL1] = read_sysreg(vbar_el1);
> ctxt->sys_regs[CONTEXTIDR_EL1] = read_sysreg(contextidr_el1);
> - ctxt->sys_regs[TPIDR_EL0] = read_sysreg(tpidr_el0);
> - ctxt->sys_regs[TPIDRRO_EL0] = read_sysreg(tpidrro_el0);
> - ctxt->sys_regs[TPIDR_EL1] = read_sysreg(tpidr_el1);
> ctxt->sys_regs[AMAIR_EL1] = read_sysreg(amair_el1);
> ctxt->sys_regs[CNTKCTL_EL1] = read_sysreg(cntkctl_el1);
> ctxt->sys_regs[PAR_EL1] = read_sysreg(par_el1);
> ctxt->sys_regs[MDSCR_EL1] = read_sysreg(mdscr_el1);
>
> - ctxt->gp_regs.regs.sp = read_sysreg(sp_el0);
> - ctxt->gp_regs.regs.pc = read_sysreg(elr_el2);
> - ctxt->gp_regs.regs.pstate = read_sysreg(spsr_el2);
> ctxt->gp_regs.sp_el1 = read_sysreg(sp_el1);
> ctxt->gp_regs.elr_el1 = read_sysreg(elr_el1);
> ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg(spsr_el1);
> @@ -60,11 +70,24 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
> void __hyp_text __sysreg_save_host_state(struct kvm_cpu_context *ctxt)
> {
> __sysreg_save_state(ctxt);
> + __sysreg_save_common_state(ctxt);
> }
>
> void __hyp_text __sysreg_save_guest_state(struct kvm_cpu_context *ctxt)
> {
> __sysreg_save_state(ctxt);
> + __sysreg_save_common_state(ctxt);
> +}
> +
> +static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
> +{
> + write_sysreg(ctxt->sys_regs[ACTLR_EL1], actlr_el1);
> + write_sysreg(ctxt->sys_regs[TPIDR_EL0], tpidr_el0);
> + write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
> + write_sysreg(ctxt->sys_regs[TPIDR_EL1], tpidr_el1);
> + write_sysreg(ctxt->gp_regs.regs.sp, sp_el0);
> + write_sysreg(ctxt->gp_regs.regs.pc, elr_el2);
> + write_sysreg(ctxt->gp_regs.regs.pstate, spsr_el2);
> }
>
> static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
> @@ -72,7 +95,6 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
> write_sysreg(ctxt->sys_regs[MPIDR_EL1], vmpidr_el2);
> write_sysreg(ctxt->sys_regs[CSSELR_EL1], csselr_el1);
> write_sysreg(ctxt->sys_regs[SCTLR_EL1], sctlr_el1);
> - write_sysreg(ctxt->sys_regs[ACTLR_EL1], actlr_el1);
> write_sysreg(ctxt->sys_regs[CPACR_EL1], cpacr_el1);
> write_sysreg(ctxt->sys_regs[TTBR0_EL1], ttbr0_el1);
> write_sysreg(ctxt->sys_regs[TTBR1_EL1], ttbr1_el1);
> @@ -84,17 +106,11 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
> write_sysreg(ctxt->sys_regs[MAIR_EL1], mair_el1);
> write_sysreg(ctxt->sys_regs[VBAR_EL1], vbar_el1);
> write_sysreg(ctxt->sys_regs[CONTEXTIDR_EL1], contextidr_el1);
> - write_sysreg(ctxt->sys_regs[TPIDR_EL0], tpidr_el0);
> - write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
> - write_sysreg(ctxt->sys_regs[TPIDR_EL1], tpidr_el1);
> write_sysreg(ctxt->sys_regs[AMAIR_EL1], amair_el1);
> write_sysreg(ctxt->sys_regs[CNTKCTL_EL1], cntkctl_el1);
> write_sysreg(ctxt->sys_regs[PAR_EL1], par_el1);
> write_sysreg(ctxt->sys_regs[MDSCR_EL1], mdscr_el1);
>
> - write_sysreg(ctxt->gp_regs.regs.sp, sp_el0);
> - write_sysreg(ctxt->gp_regs.regs.pc, elr_el2);
> - write_sysreg(ctxt->gp_regs.regs.pstate, spsr_el2);
> write_sysreg(ctxt->gp_regs.sp_el1, sp_el1);
> write_sysreg(ctxt->gp_regs.elr_el1, elr_el1);
> write_sysreg(ctxt->gp_regs.spsr[KVM_SPSR_EL1], spsr_el1);
> @@ -103,11 +119,13 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
> void __hyp_text __sysreg_restore_host_state(struct kvm_cpu_context *ctxt)
> {
> __sysreg_restore_state(ctxt);
> + __sysreg_restore_common_state(ctxt);
> }
>
> void __hyp_text __sysreg_restore_guest_state(struct kvm_cpu_context *ctxt)
> {
> __sysreg_restore_state(ctxt);
> + __sysreg_restore_common_state(ctxt);
> }
>
> void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
> --
> 2.1.4
>