[PATCH v3 16/18] KVM: arm64: nVHE: Migrate hyp interface to SMCCC
Andrew Scull
ascull at google.com
Tue Sep 8 07:02:22 EDT 2020
On Mon, Sep 07, 2020 at 03:20:07PM +0100, Marc Zyngier wrote:
> On Thu, 03 Sep 2020 14:53:05 +0100,
> Andrew Scull <ascull at google.com> wrote:
> >
> > Rather than passing arbitrary function pointers to run at hyp, define
> > and equivalent set of SMCCC functions.
> >
> > Since the SMCCC functions are strongly tied to the original function
> > prototypes, it is not expected for the host to ever call an invalid ID
> > but a warning is raised if this does ever occur.
> >
> > As __kvm_vcpu_run is used for every switch between the host and a guest,
> > it is explicitly singled out to be identified before the other function
> > IDs to improve the performance of the hot path.
> >
> > Signed-off-by: Andrew Scull <ascull at google.com>
> > Signed-off-by: David Brazdil <dbrazdil at google.com>
> > ---
> > arch/arm64/include/asm/kvm_asm.h | 24 ++++++
> > arch/arm64/include/asm/kvm_host.h | 25 ++++---
> > arch/arm64/kvm/arm.c | 2 +-
> > arch/arm64/kvm/hyp.S | 24 ++----
> > arch/arm64/kvm/hyp/nvhe/hyp-main.c | 113 +++++++++++++++++++++++++----
> > 5 files changed, 145 insertions(+), 43 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> > index 4bbde3d3989c..4a73f1349151 100644
> > --- a/arch/arm64/include/asm/kvm_asm.h
> > +++ b/arch/arm64/include/asm/kvm_asm.h
> > @@ -38,6 +38,30 @@
> >
> > #define __SMCCC_WORKAROUND_1_SMC_SZ 36
> >
> > +#define KVM_HOST_SMCCC_ID(id) \
> > + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
> > + ARM_SMCCC_SMC_64, \
> > + ARM_SMCCC_OWNER_STANDARD_HYP, \
> > + (id))
> > +
> > +#define KVM_HOST_SMCCC_FUNC(name) KVM_HOST_SMCCC_ID(__KVM_HOST_SMCCC_FUNC_##name)
> > +
> > +#define __KVM_HOST_SMCCC_FUNC___kvm_hyp_init 0
> > +#define __KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context 1
> > +#define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa 2
> > +#define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid 3
> > +#define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_local_vmid 4
> > +#define __KVM_HOST_SMCCC_FUNC___kvm_timer_set_cntvoff 5
> > +#define __KVM_HOST_SMCCC_FUNC___kvm_vcpu_run 6
> > +#define __KVM_HOST_SMCCC_FUNC___kvm_enable_ssbs 7
> > +#define __KVM_HOST_SMCCC_FUNC___vgic_v3_get_ich_vtr_el2 8
> > +#define __KVM_HOST_SMCCC_FUNC___vgic_v3_read_vmcr 9
> > +#define __KVM_HOST_SMCCC_FUNC___vgic_v3_write_vmcr 10
> > +#define __KVM_HOST_SMCCC_FUNC___vgic_v3_init_lrs 11
> > +#define __KVM_HOST_SMCCC_FUNC___kvm_get_mdcr_el2 12
> > +#define __KVM_HOST_SMCCC_FUNC___vgic_v3_save_aprs 13
> > +#define __KVM_HOST_SMCCC_FUNC___vgic_v3_restore_aprs 14
>
> Wait. This looks broken. How do you distinguish between these and the
> stubs?
The __KVM_HOST_SMCCC_FUNC_* definitions are just the function ID part of
the SMCCC x0 argument. KVM_HOST_SMCCC_ID builds it into a 64-bit
fastcall owner by the hypervisor. The stubs fall into the legacy region
so these don't conflict.
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