| Message ID | 20240222105109.2042732-4-kernel@xen0n.name (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: LoongArch: Fix wrong CPUCFG ID handling | expand |
On 2024/2/22 下午6:51, WANG Xuerui wrote: > From: WANG Xuerui <git@xen0n.name> > > All the checks currently done in kvm_check_cpucfg can be realized with > early returns, so just do that to avoid extra cognitive burden related > to the return value handling. > > While at it, clean up comments of _kvm_get_cpucfg_mask and > kvm_check_cpucfg, by removing comments that are merely restatement of > the code nearby, and paraphrasing the rest so they read more natural > for English speakers (that likely are not familiar with the actual > Chinese-influenced grammar). > > No functional changes intended. > > Signed-off-by: WANG Xuerui <git@xen0n.name> > --- > arch/loongarch/kvm/vcpu.c | 42 +++++++++++++++++++-------------------- > 1 file changed, 20 insertions(+), 22 deletions(-) > > diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c > index 9f63bbaf19c1..128b89d00ced 100644 > --- a/arch/loongarch/kvm/vcpu.c > +++ b/arch/loongarch/kvm/vcpu.c > @@ -305,20 +305,16 @@ static int _kvm_get_cpucfg_mask(int id, u64 *v) > > switch (id) { > case 2: > - /* Return CPUCFG2 features which have been supported by KVM */ > + /* CPUCFG2 features unconditionally supported by KVM */ > *v = CPUCFG2_FP | CPUCFG2_FPSP | CPUCFG2_FPDP | > CPUCFG2_FPVERS | CPUCFG2_LLFTP | CPUCFG2_LLFTPREV | > CPUCFG2_LAM; > /* > - * If LSX is supported by CPU, it is also supported by KVM, > - * as we implement it. > + * For the ISA extensions listed below, if one is supported > + * by the host, then it is also supported by KVM. > */ > if (cpu_has_lsx) > *v |= CPUCFG2_LSX; > - /* > - * if LASX is supported by CPU, it is also supported by KVM, > - * as we implement it. > - */ > if (cpu_has_lasx) > *v |= CPUCFG2_LASX; > > @@ -349,24 +345,26 @@ static int kvm_check_cpucfg(int id, u64 val) > > switch (id) { > case 2: > - /* CPUCFG2 features checking */ > if (!(val & CPUCFG2_LLFTP)) > - /* The LLFTP must be set, as guest must has a constant timer */ > - ret = -EINVAL; > - else if ((val & CPUCFG2_FP) && (!(val & CPUCFG2_FPSP) || !(val & CPUCFG2_FPDP))) > - /* Single and double float point must both be set when enable FP */ > - ret = -EINVAL; > - else if ((val & CPUCFG2_LSX) && !(val & CPUCFG2_FP)) > - /* FP should be set when enable LSX */ > - ret = -EINVAL; > - else if ((val & CPUCFG2_LASX) && !(val & CPUCFG2_LSX)) > - /* LSX, FP should be set when enable LASX, and FP has been checked before. */ > - ret = -EINVAL; > - break; > + /* Guests must have a constant timer */ > + return -EINVAL; > + if ((val & CPUCFG2_FP) && (!(val & CPUCFG2_FPSP) || !(val & CPUCFG2_FPDP))) > + /* Single and double float point must both be set when FP is enabled */ > + return -EINVAL; > + if ((val & CPUCFG2_LSX) && !(val & CPUCFG2_FP)) > + /* LSX architecturally implies FP but val does not satisfy that */ > + return -EINVAL; > + if ((val & CPUCFG2_LASX) && !(val & CPUCFG2_LSX)) > + /* LASX architecturally implies LSX and FP but val does not satisfy that */ > + return -EINVAL; > + return 0; > default: > - break; > + /* > + * Values for the other CPUCFG IDs are not being further validated > + * besides the mask check above. > + */ > + return 0; > } > - return ret; > } > > static int kvm_get_one_reg(struct kvm_vcpu *vcpu, > Reviewed-by: Bibo Mao <maobibo@loongson.cn>
diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c index 9f63bbaf19c1..128b89d00ced 100644 --- a/arch/loongarch/kvm/vcpu.c +++ b/arch/loongarch/kvm/vcpu.c @@ -305,20 +305,16 @@ static int _kvm_get_cpucfg_mask(int id, u64 *v) switch (id) { case 2: - /* Return CPUCFG2 features which have been supported by KVM */ + /* CPUCFG2 features unconditionally supported by KVM */ *v = CPUCFG2_FP | CPUCFG2_FPSP | CPUCFG2_FPDP | CPUCFG2_FPVERS | CPUCFG2_LLFTP | CPUCFG2_LLFTPREV | CPUCFG2_LAM; /* - * If LSX is supported by CPU, it is also supported by KVM, - * as we implement it. + * For the ISA extensions listed below, if one is supported + * by the host, then it is also supported by KVM. */ if (cpu_has_lsx) *v |= CPUCFG2_LSX; - /* - * if LASX is supported by CPU, it is also supported by KVM, - * as we implement it. - */ if (cpu_has_lasx) *v |= CPUCFG2_LASX; @@ -349,24 +345,26 @@ static int kvm_check_cpucfg(int id, u64 val) switch (id) { case 2: - /* CPUCFG2 features checking */ if (!(val & CPUCFG2_LLFTP)) - /* The LLFTP must be set, as guest must has a constant timer */ - ret = -EINVAL; - else if ((val & CPUCFG2_FP) && (!(val & CPUCFG2_FPSP) || !(val & CPUCFG2_FPDP))) - /* Single and double float point must both be set when enable FP */ - ret = -EINVAL; - else if ((val & CPUCFG2_LSX) && !(val & CPUCFG2_FP)) - /* FP should be set when enable LSX */ - ret = -EINVAL; - else if ((val & CPUCFG2_LASX) && !(val & CPUCFG2_LSX)) - /* LSX, FP should be set when enable LASX, and FP has been checked before. */ - ret = -EINVAL; - break; + /* Guests must have a constant timer */ + return -EINVAL; + if ((val & CPUCFG2_FP) && (!(val & CPUCFG2_FPSP) || !(val & CPUCFG2_FPDP))) + /* Single and double float point must both be set when FP is enabled */ + return -EINVAL; + if ((val & CPUCFG2_LSX) && !(val & CPUCFG2_FP)) + /* LSX architecturally implies FP but val does not satisfy that */ + return -EINVAL; + if ((val & CPUCFG2_LASX) && !(val & CPUCFG2_LSX)) + /* LASX architecturally implies LSX and FP but val does not satisfy that */ + return -EINVAL; + return 0; default: - break; + /* + * Values for the other CPUCFG IDs are not being further validated + * besides the mask check above. + */ + return 0; } - return ret; } static int kvm_get_one_reg(struct kvm_vcpu *vcpu,