Messages in this thread Patch in this message | | | Date | Wed, 11 Nov 2020 13:18:32 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH v1 15/24] kvm: arm64: Bootstrap PSCI SMC handler in nVHE EL2 |
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On 2020-11-09 11:32, David Brazdil wrote: > Add a handler of PSCI SMCs in nVHE hyp code. The handler is initialized > with the version used by the host's PSCI driver and the function IDs it > was configured with. If the SMC function ID matches one of the > configured PSCI calls (for v0.1) or falls into the PSCI function ID > range (for v0.2+), the SMC is handled by the PSCI handler. For now, all > SMCs return PSCI_RET_NOT_SUPPORTED. > > Signed-off-by: David Brazdil <dbrazdil@google.com> > --- > arch/arm64/include/asm/kvm_hyp.h | 4 ++ > arch/arm64/kvm/arm.c | 13 ++++ > arch/arm64/kvm/hyp/nvhe/Makefile | 2 +- > arch/arm64/kvm/hyp/nvhe/hyp-main.c | 4 ++ > arch/arm64/kvm/hyp/nvhe/psci.c | 102 +++++++++++++++++++++++++++++ > include/uapi/linux/psci.h | 1 + > 6 files changed, 125 insertions(+), 1 deletion(-) > create mode 100644 arch/arm64/kvm/hyp/nvhe/psci.c > > diff --git a/arch/arm64/include/asm/kvm_hyp.h > b/arch/arm64/include/asm/kvm_hyp.h > index a3289071f3d8..95a2bbbcc7e1 100644 > --- a/arch/arm64/include/asm/kvm_hyp.h > +++ b/arch/arm64/include/asm/kvm_hyp.h > @@ -96,6 +96,10 @@ void deactivate_traps_vhe_put(void); > > u64 __guest_enter(struct kvm_vcpu *vcpu); > > +#ifdef __KVM_NVHE_HYPERVISOR__ > +bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt); > +#endif > + > void __noreturn hyp_panic(void); > #ifdef __KVM_NVHE_HYPERVISOR__ > void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, > u64 par); > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index 1a57b6025937..28e3bc056225 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -19,6 +19,7 @@ > #include <linux/kvm_irqfd.h> > #include <linux/irqbypass.h> > #include <linux/sched/stat.h> > +#include <linux/psci.h> > #include <trace/events/kvm.h> > > #define CREATE_TRACE_POINTS > @@ -1498,6 +1499,17 @@ static void init_cpu_logical_map(void) > CHOOSE_NVHE_SYM(__cpu_logical_map)[cpu] = cpu_logical_map(cpu); > } > > +static void init_psci(void)
nit: init_psci_relay?
> +{ > + extern u32 kvm_nvhe_sym(kvm_host_psci_version); > + extern u32 kvm_nvhe_sym(kvm_host_psci_function_id)[PSCI_FN_MAX]; > + int i; > + > + CHOOSE_NVHE_SYM(kvm_host_psci_version) = psci_driver_version(); > + for (i = 0; i < PSCI_FN_MAX; ++i) > + CHOOSE_NVHE_SYM(kvm_host_psci_function_id)[i] = > psci_get_function_id(i); > +} > + > static int init_common_resources(void) > { > return kvm_set_ipa_limit(); > @@ -1677,6 +1689,7 @@ static int init_hyp_mode(void) > } > > init_cpu_logical_map(); > + init_psci(); > > return 0; > > diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile > b/arch/arm64/kvm/hyp/nvhe/Makefile > index c45f440cce51..647b63337a51 100644 > --- a/arch/arm64/kvm/hyp/nvhe/Makefile > +++ b/arch/arm64/kvm/hyp/nvhe/Makefile > @@ -7,7 +7,7 @@ asflags-y := -D__KVM_NVHE_HYPERVISOR__ > ccflags-y := -D__KVM_NVHE_HYPERVISOR__ > > obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o > host.o \ > - hyp-main.o percpu.o > + hyp-main.o percpu.o psci.o > obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o > ../entry.o \ > ../fpsimd.o ../hyp-entry.o > > diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c > b/arch/arm64/kvm/hyp/nvhe/hyp-main.c > index 8661bc7deaa9..69f34d4f2773 100644 > --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c > +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c > @@ -134,6 +134,10 @@ static void handle_host_smc(struct > kvm_cpu_context *host_ctxt) > */ > skip_host_instruction(); > > + /* Try to handle host's PSCI SMCs. */ > + if (kvm_host_psci_handler(host_ctxt)) > + return; > + > /* Forward SMC not handled in EL2 to EL3. */ > forward_host_smc(host_ctxt); > } > diff --git a/arch/arm64/kvm/hyp/nvhe/psci.c > b/arch/arm64/kvm/hyp/nvhe/psci.c > new file mode 100644 > index 000000000000..82d3b2c89658 > --- /dev/null > +++ b/arch/arm64/kvm/hyp/nvhe/psci.c
nit: can we please name this psci-relay.c, or psci-proxy.c? We already have a psci.c in the tree, and having the same file name messes with my editor... ;-)
> @@ -0,0 +1,102 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (C) 2020 - Google LLC > + * Author: David Brazdil <dbrazdil@google.com> > + */ > + > +#include <asm/kvm_asm.h> > +#include <asm/kvm_hyp.h> > +#include <asm/kvm_mmu.h> > +#include <kvm/arm_hypercalls.h> > +#include <linux/arm-smccc.h> > +#include <linux/psci.h> > +#include <kvm/arm_psci.h> > +#include <uapi/linux/psci.h> > + > +/* Config options set by the host. */ > +u32 kvm_host_psci_version = PSCI_VERSION(0, 0); > +u32 kvm_host_psci_function_id[PSCI_FN_MAX]; > + > +static u64 get_psci_func_id(struct kvm_cpu_context *host_ctxt) > +{ > + return host_ctxt->regs.regs[0]; > +} > + > +static bool is_psci_0_1_call(u64 func_id) > +{ > + unsigned int i; > + > + for (i = 0; i < ARRAY_SIZE(kvm_host_psci_function_id); ++i) { > + if (func_id == kvm_host_psci_function_id[i]) > + return true; > + } > + return false; > +} > + > +static bool is_psci_0_2_fn_call(u64 func_id) > +{ > + u64 base = func_id & ~PSCI_0_2_FN_ID_MASK; > + > + return base == PSCI_0_2_FN_BASE || base == PSCI_0_2_FN64_BASE;
I couldn't spot in the spec where PSCI reserves 16bit worth of IDs in each range.
> +} > + > +static bool is_psci_call(u64 func_id) > +{ > + if (kvm_host_psci_version == PSCI_VERSION(0, 0)) > + return false; > + else if (kvm_host_psci_version == PSCI_VERSION(0, 1)) > + return is_psci_0_1_call(func_id); > + else > + return is_psci_0_2_fn_call(func_id);
Consider using switch/case constructs for readability.
> +} > + > +static unsigned long psci_0_1_handler(u64 func_id, struct > kvm_cpu_context *host_ctxt) > +{ > + return PSCI_RET_NOT_SUPPORTED; > +} > + > +static unsigned long psci_0_2_handler(u64 func_id, struct > kvm_cpu_context *host_ctxt) > +{ > + switch (func_id) { > + default: > + return PSCI_RET_NOT_SUPPORTED; > + } > +} > + > +static unsigned long psci_1_0_handler(u64 func_id, struct > kvm_cpu_context *host_ctxt) > +{ > + int ret; > + > + ret = psci_0_2_handler(func_id, host_ctxt); > + if (ret != PSCI_RET_NOT_SUPPORTED) > + return ret; > + > + switch (func_id) { > + default: > + return PSCI_RET_NOT_SUPPORTED; > + }
It would probably help to adopt the same structure as we have in the KVM PSCI implementation:
switch(psci_fn) { case PSCI_0_2_FN_PSCI_VERSION: val = KVM_ARM_PSCI_1_0; break;
[...] default: return kvm_psci_0_2_call(vcpu);
which allows 1.0 to override some 0.2 functions, and otherwise leave it to the 0.2 backend.
> +} > + > +bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt) > +{ > + u64 func_id = get_psci_func_id(host_ctxt); > + unsigned long ret; > + > + if (!is_psci_call(func_id)) > + return false; > + > + if (kvm_host_psci_version == PSCI_VERSION(0, 1)) > + ret = psci_0_1_handler(func_id, host_ctxt); > + else if (kvm_host_psci_version == PSCI_VERSION(0, 2)) > + ret = psci_0_2_handler(func_id, host_ctxt); > + else if (PSCI_VERSION_MAJOR(kvm_host_psci_version) >= 1) > + ret = psci_1_0_handler(func_id, host_ctxt); > + else > + ret = PSCI_RET_NOT_SUPPORTED;
Same remark about the use of switch/case.
> + > + host_ctxt->regs.regs[0] = ret; > + host_ctxt->regs.regs[1] = 0; > + host_ctxt->regs.regs[2] = 0; > + host_ctxt->regs.regs[3] = 0; > + return true; > +} > diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h > index 2fcad1dd0b0e..0d52b8dbe8c2 100644 > --- a/include/uapi/linux/psci.h > +++ b/include/uapi/linux/psci.h > @@ -29,6 +29,7 @@ > #define PSCI_0_2_FN64_BASE \ > (PSCI_0_2_FN_BASE + PSCI_0_2_64BIT) > #define PSCI_0_2_FN64(n) (PSCI_0_2_FN64_BASE + (n)) > +#define PSCI_0_2_FN_ID_MASK 0xffff > > #define PSCI_0_2_FN_PSCI_VERSION PSCI_0_2_FN(0) > #define PSCI_0_2_FN_CPU_SUSPEND PSCI_0_2_FN(1)
Thanks,
M. -- Jazz is not dead. It just smells funny...
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