From eddabb6b888fa915ed679637983d8f39adfb725c Mon Sep 17 00:00:00 2001 From: Daniel Henrique Barboza Date: Thu, 6 Jul 2023 07:17:19 -0300 Subject: [PATCH] target/riscv: skip features setup for KVM CPUs As it is today it's not possible to use '-cpu host' if the RISC-V host has RVH enabled. This is the resulting error: $ ./qemu/build/qemu-system-riscv64 \ -machine virt,accel=kvm -m 2G -smp 1 \ -nographic -snapshot -kernel ./guest_imgs/Image \ -initrd ./guest_imgs/rootfs_kvm_riscv64.img \ -append "earlycon=sbi root=/dev/ram rw" \ -cpu host qemu-system-riscv64: H extension requires priv spec 1.12.0 This happens because we're checking for priv spec for all CPUs, and since we're not setting env->priv_ver for the 'host' CPU, it's being default to zero (i.e. PRIV_SPEC_1_10_0). In reality env->priv_ver does not make sense when running with the KVM 'host' CPU. It's used to gate certain CSRs/extensions during translation to make them unavailable if the hart declares an older spec version. It doesn't have any other use. E.g. OpenSBI version 1.2 retrieves the spec checking if the CSR_MCOUNTEREN, CSR_MCOUNTINHIBIT and CSR_MENVCFG CSRs are available [1]. 'priv_ver' is just one example. We're doing a lot of feature validation and setup during riscv_cpu_realize() that it doesn't apply to KVM CPUs. Validating the feature set for those CPUs is a KVM problem that should be handled in KVM specific code. The new riscv_cpu_realize_tcg() helper contains all validation logic that are applicable to TCG CPUs only. riscv_cpu_realize() verifies if we're running TCG and, if it's the case, proceed with the usual TCG realize() logic. [1] lib/sbi/sbi_hart.c, hart_detect_features() Signed-off-by: Daniel Henrique Barboza Reviewed-by: Andrew Jones Reviewed-by: Alistair Francis Message-Id: <20230706101738.460804-2-dbarboza@ventanamicro.com> Signed-off-by: Alistair Francis --- target/riscv/cpu.c | 35 +++++++++++++++++++++++++---------- 1 file changed, 25 insertions(+), 10 deletions(-) diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c index fd647534cf..6232e6513b 100644 --- a/target/riscv/cpu.c +++ b/target/riscv/cpu.c @@ -34,6 +34,7 @@ #include "migration/vmstate.h" #include "fpu/softfloat-helpers.h" #include "sysemu/kvm.h" +#include "sysemu/tcg.h" #include "kvm_riscv.h" #include "tcg/tcg.h" @@ -1386,20 +1387,12 @@ static void riscv_cpu_validate_misa_priv(CPURISCVState *env, Error **errp) } } -static void riscv_cpu_realize(DeviceState *dev, Error **errp) +static void riscv_cpu_realize_tcg(DeviceState *dev, Error **errp) { - CPUState *cs = CPU(dev); RISCVCPU *cpu = RISCV_CPU(dev); CPURISCVState *env = &cpu->env; - RISCVCPUClass *mcc = RISCV_CPU_GET_CLASS(dev); Error *local_err = NULL; - cpu_exec_realizefn(cs, &local_err); - if (local_err != NULL) { - error_propagate(errp, local_err); - return; - } - riscv_cpu_validate_misa_mxl(cpu, &local_err); if (local_err != NULL) { error_propagate(errp, local_err); @@ -1434,7 +1427,7 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp) } #ifndef CONFIG_USER_ONLY - cs->tcg_cflags |= CF_PCREL; + CPU(dev)->tcg_cflags |= CF_PCREL; if (cpu->cfg.ext_sstc) { riscv_timer_init(cpu); @@ -1447,6 +1440,28 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp) } } #endif +} + +static void riscv_cpu_realize(DeviceState *dev, Error **errp) +{ + CPUState *cs = CPU(dev); + RISCVCPU *cpu = RISCV_CPU(dev); + RISCVCPUClass *mcc = RISCV_CPU_GET_CLASS(dev); + Error *local_err = NULL; + + cpu_exec_realizefn(cs, &local_err); + if (local_err != NULL) { + error_propagate(errp, local_err); + return; + } + + if (tcg_enabled()) { + riscv_cpu_realize_tcg(dev, &local_err); + if (local_err != NULL) { + error_propagate(errp, local_err); + return; + } + } riscv_cpu_finalize_features(cpu, &local_err); if (local_err != NULL) {