We want to allow overwriting writable fields of some ID registers. However currently some of them are never touched, neither read nor w. Examples are CLIDR_EL1, CTR_EL0, REVIDR_EL1, MIDR_EL1.
We want to initialize them from the host value, allow overwrite and write back for kvm afterwards. This patch implements the initialization. Introduce a new get_host_cpu_idregs() helper that gets the host values for all writable ID regs and store them in isar.idregs[]. Signed-off-by: Eric Auger <[email protected]> Signed-off-by: Cornelia Huck <[email protected]> --- v5 -> v6 - do not check writable_map anymore --- target/arm/kvm.c | 98 +++++++++++++++++++++++++++++++++++++++-- target/arm/trace-events | 2 + 2 files changed, 97 insertions(+), 3 deletions(-) diff --git a/target/arm/kvm.c b/target/arm/kvm.c index 6f91407d41..71a214f228 100644 --- a/target/arm/kvm.c +++ b/target/arm/kvm.c @@ -43,6 +43,7 @@ #include "hw/acpi/ghes.h" #include "target/arm/gtimer.h" #include "migration/blocker.h" +#include "cpu-idregs.h" const KVMCapabilityInfo kvm_arch_required_capabilities[] = { KVM_CAP_INFO(DEVICE_CTRL), @@ -290,7 +291,44 @@ static int kvm_feature_idx_to_idregs_idx(int kidx) return get_sysreg_idx(sysreg); } -static void kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) +/* + * get_host_cpu_idregs: Read all the writable ID reg host values + * + * Need to be called once the writable mask has been populated + * Note we may want to read all the known id regs but some of them are not + * writable and return an error, hence the choice of reading only those which + * are writable. Those are also readable! + */ +static int get_host_cpu_idregs(ARMCPU *cpu, int fd, ARMHostCPUFeatures *ahcf) +{ + int err = 0; + int i; + + for (i = 0; i < NUM_ID_IDX; i++) { + ARM64SysReg *sysregdesc = &arm64_id_regs[i]; + ARMSysRegs sysreg = id_register_sysreg[i]; + uint64_t *reg; + int ret; + + if (!sysregdesc->writable_mask) { + continue; + } + + reg = &ahcf->isar.idregs[i]; + ret = read_sys_reg64(fd, reg, idregs_sysreg_to_kvm_reg(sysreg)); + trace_get_host_cpu_idregs(sysregdesc->name, *reg); + if (ret) { + error_report("%s error reading value of host %s register (%m)", + __func__, sysregdesc->name); + + err = ret; + } + } + return err; +} + +static void +kvm_arm_get_host_cpu_features(ARMCPU *cpu, ARMHostCPUFeatures *ahcf) { /* Identify the feature bits corresponding to the host CPU, and * fill out the ARMHostCPUClass fields accordingly. To do this @@ -376,6 +414,16 @@ static void kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) SET_IDREG(&ahcf->isar, ID_AA64PFR0, 0x00000011); /* EL1&0, AArch64 only */ err = 0; } else { + /* Make sure all writable ID reg values are initialized */ + err |= get_host_cpu_idregs(cpu, fd, ahcf); + + /* + * temporarily override the CLIDR_EL1 value since some host values + * trigger "Unified type is not implemented at level n" error in + * fdt_add_cpu_nodes() + */ + SET_IDREG(&ahcf->isar, CLIDR, 0x0); + err |= get_host_cpu_reg(fd, ahcf, ID_AA64PFR1_EL1_IDX); err |= get_host_cpu_reg(fd, ahcf, ID_AA64PFR2_EL1_IDX); err |= get_host_cpu_reg(fd, ahcf, ID_AA64SMFR0_EL1_IDX); @@ -546,7 +594,7 @@ void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu) g_free(writable_map); if (!arm_host_cpu_features.dtb_compatible) { - kvm_arm_get_host_cpu_features(&arm_host_cpu_features); + kvm_arm_get_host_cpu_features(cpu, &arm_host_cpu_features); } cpu->kvm_target = arm_host_cpu_features.target; @@ -1161,6 +1209,34 @@ bool kvm_arm_cpu_post_load(ARMCPU *cpu) return true; } +/* + * Copy writable ID regs from isar.idregs[] to cpreg_list + * in case their value differs from the original init cpreg value + */ +static void kvm_arm_writable_idregs_to_cpreg_list(ARMCPU *cpu) +{ + for (int i = 0; i < NUM_ID_IDX; i++) { + ARM64SysReg *sysregdesc = &arm64_id_regs[i]; + ARMSysRegs sysreg = id_register_sysreg[i]; + uint64_t previous, new; + uint64_t *cpreg; + + if (!sysregdesc->writable_mask) { + continue; + } + + cpreg = kvm_arm_get_cpreg_ptr(cpu, idregs_sysreg_to_kvm_reg(sysreg)); + previous = *cpreg; + new = cpu->isar.idregs[i]; + + if (previous != new) { + *cpreg = new; + trace_kvm_arm_writable_idregs_to_cpreg_list(sysregdesc->name, + previous, new); + } + } +} + void kvm_arm_reset_vcpu(ARMCPU *cpu) { int ret; @@ -2113,7 +2189,23 @@ int kvm_arch_init_vcpu(CPUState *cs) } cpu->mp_affinity = mpidr & ARM64_AFFINITY_MASK; - return kvm_arm_init_cpreg_list(cpu); + ret = kvm_arm_init_cpreg_list(cpu); + if (ret) { + return ret; + } + /* overwrite writable ID regs with their updated property values */ + kvm_arm_writable_idregs_to_cpreg_list(cpu); + ret = write_list_to_kvmstate(cpu, KVM_PUT_FULL_STATE); + if (!ret) { + return -1; + } + /* + * modified values may have changed the visibility of some regs, + * reinitialize the cpreg_list accordingly + */ + ret = kvm_arm_init_cpreg_list(cpu); + + return ret; } int kvm_arch_destroy_vcpu(CPUState *cs) diff --git a/target/arm/trace-events b/target/arm/trace-events index 8502fb3265..c25d2a1191 100644 --- a/target/arm/trace-events +++ b/target/arm/trace-events @@ -13,6 +13,8 @@ arm_gt_update_irq(int timer, int irqstate) "gt_update_irq: timer %d irqstate %d" # kvm.c kvm_arm_fixup_msi_route(uint64_t iova, uint64_t gpa) "MSI iova = 0x%"PRIx64" is translated into 0x%"PRIx64 +get_host_cpu_idregs(const char *name, uint64_t value) "scratch vcpu host value for %s is 0x%"PRIx64 +kvm_arm_writable_idregs_to_cpreg_list(const char *name, uint64_t previous, uint64_t new) "%s overwrite default 0x%"PRIx64" with 0x%"PRIx64 # cpu.c arm_cpu_reset(uint64_t mp_aff) "cpu %" PRIu64 -- 2.53.0
