Message ID | 20230622135700.105383-13-dbarboza@ventanamicro.com |
---|---|
State | New |
Headers | show |
Series | target/riscv, KVM: fixes and enhancements | expand |
On Thu, Jun 22, 2023 at 10:56:53AM -0300, Daniel Henrique Barboza wrote: ... > +#define KVM_MISA_CFG(_bit, _reg_id) \ > + {.offset = _bit, .kvm_reg_id = _reg_id} > + > +/* KVM ISA extensions */ > +static KVMCPUConfig kvm_misa_ext_cfgs[] = { > + KVM_MISA_CFG(RVA, KVM_RISCV_ISA_EXT_A), > + KVM_MISA_CFG(RVC, KVM_RISCV_ISA_EXT_C), > + KVM_MISA_CFG(RVD, KVM_RISCV_ISA_EXT_D), > + KVM_MISA_CFG(RVF, KVM_RISCV_ISA_EXT_F), > + KVM_MISA_CFG(RVH, KVM_RISCV_ISA_EXT_H), > + KVM_MISA_CFG(RVI, KVM_RISCV_ISA_EXT_I), > + KVM_MISA_CFG(RVM, KVM_RISCV_ISA_EXT_M), > +}; > + ... > +static void kvm_riscv_add_cpu_user_properties(Object *cpu_obj) > +{ > + int i; > + > + for (i = 0; i < ARRAY_SIZE(kvm_misa_ext_cfgs); i++) { > + KVMCPUConfig *misa_cfg = &kvm_misa_ext_cfgs[i]; > + int bit = misa_cfg->offset; > + > + misa_cfg->name = misa_ext_info_arr[bit].name; > + misa_cfg->description = misa_ext_info_arr[bit].description; I'd prefer these be set by KVM_MISA_CFG(), since we can. No need to wait until runtime if we can do it at compile-time. Thanks, drew > + > + object_property_add(cpu_obj, misa_cfg->name, "bool", > + NULL, > + kvm_cpu_set_misa_ext_cfg, > + NULL, misa_cfg); > + object_property_set_description(cpu_obj, misa_cfg->name, > + misa_cfg->description); > + } > +} > + > static int kvm_riscv_get_regs_core(CPUState *cs) > { > int ret = 0; > @@ -427,6 +504,7 @@ void kvm_riscv_init_user_properties(Object *cpu_obj) > return; > } > > + kvm_riscv_add_cpu_user_properties(cpu_obj); > kvm_riscv_init_machine_ids(cpu, &kvmcpu); > kvm_riscv_init_misa_ext_mask(cpu, &kvmcpu); > > -- > 2.41.0 >
On 6/23/23 06:38, Andrew Jones wrote: > On Thu, Jun 22, 2023 at 10:56:53AM -0300, Daniel Henrique Barboza wrote: > ... >> +#define KVM_MISA_CFG(_bit, _reg_id) \ >> + {.offset = _bit, .kvm_reg_id = _reg_id} >> + >> +/* KVM ISA extensions */ >> +static KVMCPUConfig kvm_misa_ext_cfgs[] = { >> + KVM_MISA_CFG(RVA, KVM_RISCV_ISA_EXT_A), >> + KVM_MISA_CFG(RVC, KVM_RISCV_ISA_EXT_C), >> + KVM_MISA_CFG(RVD, KVM_RISCV_ISA_EXT_D), >> + KVM_MISA_CFG(RVF, KVM_RISCV_ISA_EXT_F), >> + KVM_MISA_CFG(RVH, KVM_RISCV_ISA_EXT_H), >> + KVM_MISA_CFG(RVI, KVM_RISCV_ISA_EXT_I), >> + KVM_MISA_CFG(RVM, KVM_RISCV_ISA_EXT_M), >> +}; >> + > ... >> +static void kvm_riscv_add_cpu_user_properties(Object *cpu_obj) >> +{ >> + int i; >> + >> + for (i = 0; i < ARRAY_SIZE(kvm_misa_ext_cfgs); i++) { >> + KVMCPUConfig *misa_cfg = &kvm_misa_ext_cfgs[i]; >> + int bit = misa_cfg->offset; >> + >> + misa_cfg->name = misa_ext_info_arr[bit].name; >> + misa_cfg->description = misa_ext_info_arr[bit].description; > > I'd prefer these be set by KVM_MISA_CFG(), since we can. No need to wait > until runtime if we can do it at compile-time. The compiler will complain about "error: initializer element is not constant" and the build will fail. This happens because, apparently, the compiler doesn't see the imported array as a constant, regardless of the 'const' type. If there's a trick that allow us to set these inside that macro I'm all ears. I tried a bit, failed, and ended up adding these 2 extra lines. Thanks, Daniel > > Thanks, > drew > >> + >> + object_property_add(cpu_obj, misa_cfg->name, "bool", >> + NULL, >> + kvm_cpu_set_misa_ext_cfg, >> + NULL, misa_cfg); >> + object_property_set_description(cpu_obj, misa_cfg->name, >> + misa_cfg->description); >> + } >> +} >> + >> static int kvm_riscv_get_regs_core(CPUState *cs) >> { >> int ret = 0; >> @@ -427,6 +504,7 @@ void kvm_riscv_init_user_properties(Object *cpu_obj) >> return; >> } >> >> + kvm_riscv_add_cpu_user_properties(cpu_obj); >> kvm_riscv_init_machine_ids(cpu, &kvmcpu); >> kvm_riscv_init_misa_ext_mask(cpu, &kvmcpu); >> >> -- >> 2.41.0 >>
On Fri, Jun 23, 2023 at 11:14:45AM -0300, Daniel Henrique Barboza wrote: > > > On 6/23/23 06:38, Andrew Jones wrote: > > On Thu, Jun 22, 2023 at 10:56:53AM -0300, Daniel Henrique Barboza wrote: > > ... > > > +#define KVM_MISA_CFG(_bit, _reg_id) \ > > > + {.offset = _bit, .kvm_reg_id = _reg_id} > > > + > > > +/* KVM ISA extensions */ > > > +static KVMCPUConfig kvm_misa_ext_cfgs[] = { > > > + KVM_MISA_CFG(RVA, KVM_RISCV_ISA_EXT_A), > > > + KVM_MISA_CFG(RVC, KVM_RISCV_ISA_EXT_C), > > > + KVM_MISA_CFG(RVD, KVM_RISCV_ISA_EXT_D), > > > + KVM_MISA_CFG(RVF, KVM_RISCV_ISA_EXT_F), > > > + KVM_MISA_CFG(RVH, KVM_RISCV_ISA_EXT_H), > > > + KVM_MISA_CFG(RVI, KVM_RISCV_ISA_EXT_I), > > > + KVM_MISA_CFG(RVM, KVM_RISCV_ISA_EXT_M), > > > +}; > > > + > > ... > > > +static void kvm_riscv_add_cpu_user_properties(Object *cpu_obj) > > > +{ > > > + int i; > > > + > > > + for (i = 0; i < ARRAY_SIZE(kvm_misa_ext_cfgs); i++) { > > > + KVMCPUConfig *misa_cfg = &kvm_misa_ext_cfgs[i]; > > > + int bit = misa_cfg->offset; > > > + > > > + misa_cfg->name = misa_ext_info_arr[bit].name; > > > + misa_cfg->description = misa_ext_info_arr[bit].description; > > > > I'd prefer these be set by KVM_MISA_CFG(), since we can. No need to wait > > until runtime if we can do it at compile-time. > > The compiler will complain about "error: initializer element is not constant" and > the build will fail. This happens because, apparently, the compiler doesn't see the > imported array as a constant, regardless of the 'const' type. > You're right. Initialization the way I suggested only works when everything is in the same source file. That's a pity. So we can either manage it they way you've done here or the way you did in a previous patch, which was to include the info array in each source file by putting it in the header. I think I prefer the approach you used in this version more though. Thanks, drew
On 6/24/23 04:32, Andrew Jones wrote: > On Fri, Jun 23, 2023 at 11:14:45AM -0300, Daniel Henrique Barboza wrote: >> >> >> On 6/23/23 06:38, Andrew Jones wrote: >>> On Thu, Jun 22, 2023 at 10:56:53AM -0300, Daniel Henrique Barboza wrote: >>> ... >>>> +#define KVM_MISA_CFG(_bit, _reg_id) \ >>>> + {.offset = _bit, .kvm_reg_id = _reg_id} >>>> + >>>> +/* KVM ISA extensions */ >>>> +static KVMCPUConfig kvm_misa_ext_cfgs[] = { >>>> + KVM_MISA_CFG(RVA, KVM_RISCV_ISA_EXT_A), >>>> + KVM_MISA_CFG(RVC, KVM_RISCV_ISA_EXT_C), >>>> + KVM_MISA_CFG(RVD, KVM_RISCV_ISA_EXT_D), >>>> + KVM_MISA_CFG(RVF, KVM_RISCV_ISA_EXT_F), >>>> + KVM_MISA_CFG(RVH, KVM_RISCV_ISA_EXT_H), >>>> + KVM_MISA_CFG(RVI, KVM_RISCV_ISA_EXT_I), >>>> + KVM_MISA_CFG(RVM, KVM_RISCV_ISA_EXT_M), >>>> +}; >>>> + >>> ... >>>> +static void kvm_riscv_add_cpu_user_properties(Object *cpu_obj) >>>> +{ >>>> + int i; >>>> + >>>> + for (i = 0; i < ARRAY_SIZE(kvm_misa_ext_cfgs); i++) { >>>> + KVMCPUConfig *misa_cfg = &kvm_misa_ext_cfgs[i]; >>>> + int bit = misa_cfg->offset; >>>> + >>>> + misa_cfg->name = misa_ext_info_arr[bit].name; >>>> + misa_cfg->description = misa_ext_info_arr[bit].description; >>> >>> I'd prefer these be set by KVM_MISA_CFG(), since we can. No need to wait >>> until runtime if we can do it at compile-time. >> >> The compiler will complain about "error: initializer element is not constant" and >> the build will fail. This happens because, apparently, the compiler doesn't see the >> imported array as a constant, regardless of the 'const' type. >> > > You're right. Initialization the way I suggested only works when > everything is in the same source file. That's a pity. So we can > either manage it they way you've done here or the way you did > in a previous patch, which was to include the info array in each > source file by putting it in the header. I think I prefer the > approach you used in this version more though. Alright, let's keep this version then. Btw I just noticed that I kept your reviewed-by from the previous version in this patch by accident. Can you please send a r-b for this version (in case you agree, of course)? Thanks, Daniel > > Thanks, > drew
On Thu, Jun 22, 2023 at 10:56:53AM -0300, Daniel Henrique Barboza wrote: > Using all TCG user properties in KVM is tricky. First because KVM > supports only a small subset of what TCG provides, so most of the > cpu->cfg flags do nothing for KVM. > > Second, and more important, we don't have a way of telling if any given > value is an user input or not. For TCG this has a small impact since we > just validating everything and error out if needed. But for KVM it would > be good to know if a given value was set by the user or if it's a value > already provided by KVM. Otherwise we don't know how to handle failed > kvm_set_one_regs() when writing the configurations back. > > These characteristics make it overly complicated to use the same user > facing flags for both KVM and TCG. A simpler approach is to create KVM > specific properties that have specialized logic, forking KVM and TCG use > cases for those cases only. Fully separating KVM/TCG properties is > unneeded at this point - in fact we want the user experience to be as > equal as possible, regardless of the acceleration chosen. > > We'll start this fork with the MISA properties, adding the MISA bits > that the KVM driver currently supports. A new KVMCPUConfig type is > introduced. It'll hold general information about an extension. For MISA > extensions we're going to use the newly created misa_ext_infos[] to > populate their name and description. 'offset' holds the MISA bit (RVA, > RVC, ...). We're calling it 'offset' instead of 'misa_bit' because this > same KVMCPUConfig struct will be used to multi-letter extensions later > on. > > This new type also holds a 'user_set' flag. This flag will be set when > the user set an option that's different than what is already configured > in the host, requiring KVM intervention to write the regs back during > kvm_arch_init_vcpu(). Similar mechanics will be implemented for > multi-letter extensions as well. > > There is no need to duplicate more code than necessary, so we're going > to use the existing kvm_riscv_init_user_properties() to add the KVM > specific properties. Any code that is adding a TCG user prop is then > changed slightly to verify first if there's a KVM prop with the same > name already added. > > Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com> > Reviewed-by: Andrew Jones <ajones@ventanamicro.com> > --- > target/riscv/cpu.c | 10 ++++++ > target/riscv/kvm.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 88 insertions(+) > Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c index 0e5d8b05a2..5a50cb1d0b 100644 --- a/target/riscv/cpu.c +++ b/target/riscv/cpu.c @@ -1610,6 +1610,11 @@ static void riscv_cpu_add_misa_properties(Object *cpu_obj) for (i = 0; i < ARRAY_SIZE(misa_ext_cfgs); i++) { const RISCVCPUMisaExtConfig *misa_cfg = &misa_ext_cfgs[i]; + /* Check if KVM didn't create the property already */ + if (object_property_find(cpu_obj, misa_cfg->name)) { + continue; + } + object_property_add(cpu_obj, misa_cfg->name, "bool", cpu_get_misa_ext_cfg, cpu_set_misa_ext_cfg, @@ -1733,6 +1738,11 @@ static void riscv_cpu_add_user_properties(Object *obj) riscv_cpu_add_misa_properties(obj); for (prop = riscv_cpu_extensions; prop && prop->name; prop++) { + /* Check if KVM didn't create the property already */ + if (object_property_find(obj, prop->name)) { + continue; + } + qdev_property_add_static(dev, prop); } diff --git a/target/riscv/kvm.c b/target/riscv/kvm.c index 4d0808cb9a..fb5c5d4bfc 100644 --- a/target/riscv/kvm.c +++ b/target/riscv/kvm.c @@ -22,8 +22,10 @@ #include <linux/kvm.h> #include "qemu/timer.h" +#include "qapi/error.h" #include "qemu/error-report.h" #include "qemu/main-loop.h" +#include "qapi/visitor.h" #include "sysemu/sysemu.h" #include "sysemu/kvm.h" #include "sysemu/kvm_int.h" @@ -105,6 +107,81 @@ static uint64_t kvm_riscv_reg_id(CPURISCVState *env, uint64_t type, } \ } while (0) +typedef struct KVMCPUConfig { + const char *name; + const char *description; + target_ulong offset; + int kvm_reg_id; + bool user_set; +} KVMCPUConfig; + +#define KVM_MISA_CFG(_bit, _reg_id) \ + {.offset = _bit, .kvm_reg_id = _reg_id} + +/* KVM ISA extensions */ +static KVMCPUConfig kvm_misa_ext_cfgs[] = { + KVM_MISA_CFG(RVA, KVM_RISCV_ISA_EXT_A), + KVM_MISA_CFG(RVC, KVM_RISCV_ISA_EXT_C), + KVM_MISA_CFG(RVD, KVM_RISCV_ISA_EXT_D), + KVM_MISA_CFG(RVF, KVM_RISCV_ISA_EXT_F), + KVM_MISA_CFG(RVH, KVM_RISCV_ISA_EXT_H), + KVM_MISA_CFG(RVI, KVM_RISCV_ISA_EXT_I), + KVM_MISA_CFG(RVM, KVM_RISCV_ISA_EXT_M), +}; + +static void kvm_cpu_set_misa_ext_cfg(Object *obj, Visitor *v, + const char *name, + void *opaque, Error **errp) +{ + KVMCPUConfig *misa_ext_cfg = opaque; + target_ulong misa_bit = misa_ext_cfg->offset; + RISCVCPU *cpu = RISCV_CPU(obj); + CPURISCVState *env = &cpu->env; + bool value, host_bit; + + if (!visit_type_bool(v, name, &value, errp)) { + return; + } + + host_bit = env->misa_ext_mask & misa_bit; + + if (value == host_bit) { + return; + } + + if (!value) { + misa_ext_cfg->user_set = true; + return; + } + + /* + * Forbid users to enable extensions that aren't + * available in the hart. + */ + error_setg(errp, "Enabling MISA bit '%s' is not allowed: it's not " + "enabled in the host", misa_ext_cfg->name); +} + +static void kvm_riscv_add_cpu_user_properties(Object *cpu_obj) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(kvm_misa_ext_cfgs); i++) { + KVMCPUConfig *misa_cfg = &kvm_misa_ext_cfgs[i]; + int bit = misa_cfg->offset; + + misa_cfg->name = misa_ext_info_arr[bit].name; + misa_cfg->description = misa_ext_info_arr[bit].description; + + object_property_add(cpu_obj, misa_cfg->name, "bool", + NULL, + kvm_cpu_set_misa_ext_cfg, + NULL, misa_cfg); + object_property_set_description(cpu_obj, misa_cfg->name, + misa_cfg->description); + } +} + static int kvm_riscv_get_regs_core(CPUState *cs) { int ret = 0; @@ -427,6 +504,7 @@ void kvm_riscv_init_user_properties(Object *cpu_obj) return; } + kvm_riscv_add_cpu_user_properties(cpu_obj); kvm_riscv_init_machine_ids(cpu, &kvmcpu); kvm_riscv_init_misa_ext_mask(cpu, &kvmcpu);