| Message ID | 20220817214818.3243383-3-oliver.upton@linux.dev (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Treat 32bit ID registers as RAZ/WI on 64bit-only system | expand |
Hi Oliver, On Wed, Aug 17, 2022 at 2:48 PM Oliver Upton <oliver.upton@linux.dev> wrote: > > The internal accessors are only ever called once. Dump out their > contents in the caller. > > No functional change intended. > > Signed-off-by: Oliver Upton <oliver.upton@linux.dev> > --- > arch/arm64/kvm/sys_regs.c | 46 ++++++++++----------------------------- > 1 file changed, 12 insertions(+), 34 deletions(-) > > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index e18efb9211f0..26210f3a0b27 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -1153,25 +1153,17 @@ static unsigned int raz_visibility(const struct kvm_vcpu *vcpu, > > /* cpufeature ID register access trap handlers */ > > -static bool __access_id_reg(struct kvm_vcpu *vcpu, > - struct sys_reg_params *p, > - const struct sys_reg_desc *r, > - bool raz) > -{ > - if (p->is_write) > - return write_to_read_only(vcpu, p, r); > - > - p->regval = read_id_reg(vcpu, r, raz); > - return true; > -} > - > static bool access_id_reg(struct kvm_vcpu *vcpu, > struct sys_reg_params *p, > const struct sys_reg_desc *r) > { > bool raz = sysreg_visible_as_raz(vcpu, r); > > - return __access_id_reg(vcpu, p, r, raz); > + if (p->is_write) > + return write_to_read_only(vcpu, p, r); > + > + p->regval = read_id_reg(vcpu, r, raz); > + return true; > } > > /* Visibility overrides for SVE-specific control registers */ > @@ -1226,31 +1218,13 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu, > * are stored, and for set_id_reg() we don't allow the effective value > * to be changed. > */ > -static int __get_id_reg(const struct kvm_vcpu *vcpu, > - const struct sys_reg_desc *rd, u64 *val, > - bool raz) > -{ > - *val = read_id_reg(vcpu, rd, raz); > - return 0; > -} > - > -static int __set_id_reg(const struct kvm_vcpu *vcpu, > - const struct sys_reg_desc *rd, u64 val, > - bool raz) > -{ > - /* This is what we mean by invariant: you can't change it. */ > - if (val != read_id_reg(vcpu, rd, raz)) > - return -EINVAL; > - > - return 0; > -} > - > static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, > u64 *val) > { > bool raz = sysreg_visible_as_raz(vcpu, rd); > > - return __get_id_reg(vcpu, rd, val, raz); > + *val = read_id_reg(vcpu, rd, raz); > + return 0; > } > > static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, > @@ -1258,7 +1232,11 @@ static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, > { > bool raz = sysreg_visible_as_raz(vcpu, rd); > > - return __set_id_reg(vcpu, rd, val, raz); > + /* This is what we mean by invariant: you can't change it. */ > + if (val != read_id_reg(vcpu, rd, raz)) > + return -EINVAL; > + > + return 0; > } I see no reason for read_id_reg() to take raz as an argument. Perhaps having read_id_reg() call sysreg_visible_as_raz() instead might make those functions even simpler? Thank you, Reiji
Hi Reiji, On Mon, Aug 29, 2022 at 10:45:09PM -0700, Reiji Watanabe wrote: > Hi Oliver, > > On Wed, Aug 17, 2022 at 2:48 PM Oliver Upton <oliver.upton@linux.dev> wrote: > > > > The internal accessors are only ever called once. Dump out their > > contents in the caller. > > > > No functional change intended. > > > > Signed-off-by: Oliver Upton <oliver.upton@linux.dev> > > --- > > arch/arm64/kvm/sys_regs.c | 46 ++++++++++----------------------------- > > 1 file changed, 12 insertions(+), 34 deletions(-) > > > > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > > index e18efb9211f0..26210f3a0b27 100644 > > --- a/arch/arm64/kvm/sys_regs.c > > +++ b/arch/arm64/kvm/sys_regs.c > > @@ -1153,25 +1153,17 @@ static unsigned int raz_visibility(const struct kvm_vcpu *vcpu, > > > > /* cpufeature ID register access trap handlers */ > > > > -static bool __access_id_reg(struct kvm_vcpu *vcpu, > > - struct sys_reg_params *p, > > - const struct sys_reg_desc *r, > > - bool raz) > > -{ > > - if (p->is_write) > > - return write_to_read_only(vcpu, p, r); > > - > > - p->regval = read_id_reg(vcpu, r, raz); > > - return true; > > -} > > - > > static bool access_id_reg(struct kvm_vcpu *vcpu, > > struct sys_reg_params *p, > > const struct sys_reg_desc *r) > > { > > bool raz = sysreg_visible_as_raz(vcpu, r); > > > > - return __access_id_reg(vcpu, p, r, raz); > > + if (p->is_write) > > + return write_to_read_only(vcpu, p, r); > > + > > + p->regval = read_id_reg(vcpu, r, raz); > > + return true; > > } > > > > /* Visibility overrides for SVE-specific control registers */ > > @@ -1226,31 +1218,13 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu, > > * are stored, and for set_id_reg() we don't allow the effective value > > * to be changed. > > */ > > -static int __get_id_reg(const struct kvm_vcpu *vcpu, > > - const struct sys_reg_desc *rd, u64 *val, > > - bool raz) > > -{ > > - *val = read_id_reg(vcpu, rd, raz); > > - return 0; > > -} > > - > > -static int __set_id_reg(const struct kvm_vcpu *vcpu, > > - const struct sys_reg_desc *rd, u64 val, > > - bool raz) > > -{ > > - /* This is what we mean by invariant: you can't change it. */ > > - if (val != read_id_reg(vcpu, rd, raz)) > > - return -EINVAL; > > - > > - return 0; > > -} > > - > > static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, > > u64 *val) > > { > > bool raz = sysreg_visible_as_raz(vcpu, rd); > > > > - return __get_id_reg(vcpu, rd, val, raz); > > + *val = read_id_reg(vcpu, rd, raz); > > + return 0; > > } > > > > static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, > > @@ -1258,7 +1232,11 @@ static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, > > { > > bool raz = sysreg_visible_as_raz(vcpu, rd); > > > > - return __set_id_reg(vcpu, rd, val, raz); > > + /* This is what we mean by invariant: you can't change it. */ > > + if (val != read_id_reg(vcpu, rd, raz)) > > + return -EINVAL; > > + > > + return 0; > > } > > I see no reason for read_id_reg() to take raz as an argument. > Perhaps having read_id_reg() call sysreg_visible_as_raz() instead > might make those functions even simpler? Good point, as this patch has done away with caller-specified RAZ. I'll incorporate that into v2. -- Best, Oliver
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index e18efb9211f0..26210f3a0b27 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1153,25 +1153,17 @@ static unsigned int raz_visibility(const struct kvm_vcpu *vcpu, /* cpufeature ID register access trap handlers */ -static bool __access_id_reg(struct kvm_vcpu *vcpu, - struct sys_reg_params *p, - const struct sys_reg_desc *r, - bool raz) -{ - if (p->is_write) - return write_to_read_only(vcpu, p, r); - - p->regval = read_id_reg(vcpu, r, raz); - return true; -} - static bool access_id_reg(struct kvm_vcpu *vcpu, struct sys_reg_params *p, const struct sys_reg_desc *r) { bool raz = sysreg_visible_as_raz(vcpu, r); - return __access_id_reg(vcpu, p, r, raz); + if (p->is_write) + return write_to_read_only(vcpu, p, r); + + p->regval = read_id_reg(vcpu, r, raz); + return true; } /* Visibility overrides for SVE-specific control registers */ @@ -1226,31 +1218,13 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu, * are stored, and for set_id_reg() we don't allow the effective value * to be changed. */ -static int __get_id_reg(const struct kvm_vcpu *vcpu, - const struct sys_reg_desc *rd, u64 *val, - bool raz) -{ - *val = read_id_reg(vcpu, rd, raz); - return 0; -} - -static int __set_id_reg(const struct kvm_vcpu *vcpu, - const struct sys_reg_desc *rd, u64 val, - bool raz) -{ - /* This is what we mean by invariant: you can't change it. */ - if (val != read_id_reg(vcpu, rd, raz)) - return -EINVAL; - - return 0; -} - static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, u64 *val) { bool raz = sysreg_visible_as_raz(vcpu, rd); - return __get_id_reg(vcpu, rd, val, raz); + *val = read_id_reg(vcpu, rd, raz); + return 0; } static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, @@ -1258,7 +1232,11 @@ static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, { bool raz = sysreg_visible_as_raz(vcpu, rd); - return __set_id_reg(vcpu, rd, val, raz); + /* This is what we mean by invariant: you can't change it. */ + if (val != read_id_reg(vcpu, rd, raz)) + return -EINVAL; + + return 0; } static int get_raz_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
The internal accessors are only ever called once. Dump out their contents in the caller. No functional change intended. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> --- arch/arm64/kvm/sys_regs.c | 46 ++++++++++----------------------------- 1 file changed, 12 insertions(+), 34 deletions(-)