| Message ID | 20240222105109.2042732-2-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> > > The range check for the CPUCFG ID is wrong (should have been a || > instead of &&) and useless in effect, so fix the obvious mistake. > > Furthermore, the juggling of the temp return value is unnecessary, > because it is semantically equivalent and more readable to just > return at every switch case's end. This is done too to avoid potential > bugs in the future related to the unwanted complexity. > > Also, the return value of _kvm_get_cpucfg is meant to be checked, but > this was not done, so bad CPUCFG IDs wrongly fall back to the default > case and 0 is incorrectly returned; check the return value to fix the > UAPI behavior. > > While at it, also remove the redundant range check in kvm_check_cpucfg, > because out-of-range CPUCFG IDs are already rejected by the -EINVAL > as returned by _kvm_get_cpucfg. > > Fixes: db1ecca22edf ("LoongArch: KVM: Add LSX (128bit SIMD) support") > Fixes: 118e10cd893d ("LoongArch: KVM: Add LASX (256bit SIMD) support") > Signed-off-by: WANG Xuerui <git@xen0n.name> > --- > arch/loongarch/kvm/vcpu.c | 35 ++++++++++++++++++----------------- > 1 file changed, 18 insertions(+), 17 deletions(-) > > diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c > index 27701991886d..7fd32de6656b 100644 > --- a/arch/loongarch/kvm/vcpu.c > +++ b/arch/loongarch/kvm/vcpu.c > @@ -300,9 +300,7 @@ static int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 val) > > static int _kvm_get_cpucfg(int id, u64 *v) > { > - int ret = 0; > - > - if (id < 0 && id >= KVM_MAX_CPUCFG_REGS) > + if (id < 0 || id >= KVM_MAX_CPUCFG_REGS) > return -EINVAL; > > switch (id) { > @@ -324,32 +322,35 @@ static int _kvm_get_cpucfg(int id, u64 *v) > if (cpu_has_lasx) > *v |= CPUCFG2_LASX; > > - break; > + return 0; > default: > - ret = -EINVAL; > - break; > + /* > + * No restrictions on other valid CPUCFG IDs' values, but > + * CPUCFG data is limited to 32 bits as the LoongArch ISA > + * manual says (Volume 1, Section 2.2.10.5 "CPUCFG"). > + */ > + *v = U32_MAX; > + return 0; > } > - return ret; > } > > static int kvm_check_cpucfg(int id, u64 val) > { > - u64 mask; > - int ret = 0; > - > - if (id < 0 && id >= KVM_MAX_CPUCFG_REGS) > - return -EINVAL; > + u64 mask = 0; > + int ret; > > - if (_kvm_get_cpucfg(id, &mask)) > + ret = _kvm_get_cpucfg(id, &mask); > + if (ret) > return ret; > > + if (val & ~mask) > + /* Unsupported features and/or the higher 32 bits should not be set */ > + return -EINVAL; > + > switch (id) { > case 2: > /* CPUCFG2 features checking */ > - if (val & ~mask) > - /* The unsupported features should not be set */ > - ret = -EINVAL; > - else if (!(val & CPUCFG2_LLFTP)) > + 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))) > Thanks for your contributions -:) Reviewed-by: Bibo Mao <maobibo@loongson.cn>
diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c index 27701991886d..7fd32de6656b 100644 --- a/arch/loongarch/kvm/vcpu.c +++ b/arch/loongarch/kvm/vcpu.c @@ -300,9 +300,7 @@ static int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 val) static int _kvm_get_cpucfg(int id, u64 *v) { - int ret = 0; - - if (id < 0 && id >= KVM_MAX_CPUCFG_REGS) + if (id < 0 || id >= KVM_MAX_CPUCFG_REGS) return -EINVAL; switch (id) { @@ -324,32 +322,35 @@ static int _kvm_get_cpucfg(int id, u64 *v) if (cpu_has_lasx) *v |= CPUCFG2_LASX; - break; + return 0; default: - ret = -EINVAL; - break; + /* + * No restrictions on other valid CPUCFG IDs' values, but + * CPUCFG data is limited to 32 bits as the LoongArch ISA + * manual says (Volume 1, Section 2.2.10.5 "CPUCFG"). + */ + *v = U32_MAX; + return 0; } - return ret; } static int kvm_check_cpucfg(int id, u64 val) { - u64 mask; - int ret = 0; - - if (id < 0 && id >= KVM_MAX_CPUCFG_REGS) - return -EINVAL; + u64 mask = 0; + int ret; - if (_kvm_get_cpucfg(id, &mask)) + ret = _kvm_get_cpucfg(id, &mask); + if (ret) return ret; + if (val & ~mask) + /* Unsupported features and/or the higher 32 bits should not be set */ + return -EINVAL; + switch (id) { case 2: /* CPUCFG2 features checking */ - if (val & ~mask) - /* The unsupported features should not be set */ - ret = -EINVAL; - else if (!(val & CPUCFG2_LLFTP)) + 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)))