Messages in this thread | | | Date | Thu, 03 Dec 2020 13:31:18 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH v4 15/26] kvm: arm64: Add SMC handler in nVHE EL2 |
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On 2020-12-02 18:41, David Brazdil wrote: > Add handler of host SMCs in KVM nVHE trap handler. Forward all SMCs to > EL3 and propagate the result back to EL1. This is done in preparation > for validating host SMCs in KVM protected mode. > > The implementation assumes that firmware uses SMCCC v1.2 or older. That > means x0-x17 can be used both for arguments and results, other GPRs are > preserved. > > Signed-off-by: David Brazdil <dbrazdil@google.com> > --- > arch/arm64/kvm/hyp/nvhe/host.S | 38 ++++++++++++++++++++++++++++++ > arch/arm64/kvm/hyp/nvhe/hyp-main.c | 35 ++++++++++++++++++++++++--- > 2 files changed, 70 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kvm/hyp/nvhe/host.S > b/arch/arm64/kvm/hyp/nvhe/host.S > index fe2740b224cf..2b56f0bdf874 100644 > --- a/arch/arm64/kvm/hyp/nvhe/host.S > +++ b/arch/arm64/kvm/hyp/nvhe/host.S > @@ -180,3 +180,41 @@ SYM_CODE_START(__kvm_hyp_host_vector) > invalid_host_el1_vect // FIQ 32-bit EL1 > invalid_host_el1_vect // Error 32-bit EL1 > SYM_CODE_END(__kvm_hyp_host_vector) > + > +/* > + * Forward SMC with arguments in struct kvm_cpu_context, and > + * store the result into the same struct. Assumes SMCCC 1.2 or older. > + * > + * x0: struct kvm_cpu_context* > + */ > +SYM_CODE_START(__kvm_hyp_host_forward_smc) > + /* > + * Use x18 to keep the pointer to the host context because > + * x18 is callee-saved in SMCCC but not in AAPCS64. > + */ > + mov x18, x0 > + > + ldp x0, x1, [x18, #CPU_XREG_OFFSET(0)] > + ldp x2, x3, [x18, #CPU_XREG_OFFSET(2)] > + ldp x4, x5, [x18, #CPU_XREG_OFFSET(4)] > + ldp x6, x7, [x18, #CPU_XREG_OFFSET(6)] > + ldp x8, x9, [x18, #CPU_XREG_OFFSET(8)] > + ldp x10, x11, [x18, #CPU_XREG_OFFSET(10)] > + ldp x12, x13, [x18, #CPU_XREG_OFFSET(12)] > + ldp x14, x15, [x18, #CPU_XREG_OFFSET(14)] > + ldp x16, x17, [x18, #CPU_XREG_OFFSET(16)] > + > + smc #0 > + > + stp x0, x1, [x18, #CPU_XREG_OFFSET(0)] > + stp x2, x3, [x18, #CPU_XREG_OFFSET(2)] > + stp x4, x5, [x18, #CPU_XREG_OFFSET(4)] > + stp x6, x7, [x18, #CPU_XREG_OFFSET(6)] > + stp x8, x9, [x18, #CPU_XREG_OFFSET(8)] > + stp x10, x11, [x18, #CPU_XREG_OFFSET(10)] > + stp x12, x13, [x18, #CPU_XREG_OFFSET(12)] > + stp x14, x15, [x18, #CPU_XREG_OFFSET(14)] > + stp x16, x17, [x18, #CPU_XREG_OFFSET(16)] > + > + ret > +SYM_CODE_END(__kvm_hyp_host_forward_smc) > diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c > b/arch/arm64/kvm/hyp/nvhe/hyp-main.c > index a4f1cac714d7..f25680ede080 100644 > --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c > +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c > @@ -18,6 +18,8 @@ > > DEFINE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params); > > +void __kvm_hyp_host_forward_smc(struct kvm_cpu_context *host_ctxt); > + > static void handle___kvm_vcpu_run(struct kvm_cpu_context *host_ctxt) > { > DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1); > @@ -152,12 +154,39 @@ static void handle_host_hcall(struct > kvm_cpu_context *host_ctxt) > cpu_reg(host_ctxt, 0) = SMCCC_RET_NOT_SUPPORTED; > } > > +static void default_host_smc_handler(struct kvm_cpu_context > *host_ctxt) > +{ > + __kvm_hyp_host_forward_smc(host_ctxt); > +} > + > +static void skip_host_instruction(void) > +{ > + write_sysreg_el2(read_sysreg_el2(SYS_ELR) + 4, SYS_ELR); > +}
Just for the sake of keeping things together, it'd be good to move this helper to include/hyp/adjust_pc.h. Nothing urgent though.
Thanks,
M. -- Jazz is not dead. It just smells funny...
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