[PATCH 00/19] KVM: arm64: vgic-v3 userspace access consolidation (and other goodies)

[PATCH 00/19] KVM: arm64: vgic-v3 userspace access consolidation (and other goodies)

[Marc Zyngier]

Schspa Shi recently reported[1] that some of the vgic code interacting
with userspace was reading uninitialised stack memory, and although
that read wasn't used any further, it prompted me to revisit this part
of the code.

Needless to say, this area of the kernel is pretty crufty, and shows a
bunch of issues in other parts of the KVM/arm64 infrastructure. This
series tries to remedy a bunch of them:

- Sanitise the way we deal with sysregs from userspace: at the moment,
  each and every .set_user/.get_user callback has to implement its own
  userspace accesses (directly or indirectly). It'd be much better if
  that was centralised so that we can reason about it.

- Enforce that all AArch64 sysregs are 64bit. Always. This was sort of
  implied by the code, but it took some effort to convince myself that
  this was actually the case.

- Move the vgic-v3 sysreg userspace accessors to the userspace
  callbacks instead of hijacking the vcpu trap callback. This allows
  us to reuse the sysreg infrastructure.

- Consolidate userspace accesses for both GICv2, GICv3 and common code
  as much as possible.

- Cleanup a bunch of not-very-useful helpers, tidy up some of the code
  as we touch it.

Overall, this is essentially a cosmetic exercise, as there is no new
feature here. But I have the feeling that the result is somehow more
maintainable. This has been (lightly) tested on my Synquacer, and
nothing exploded. Yet. YMMV.

[1] https://lore.kernel.org/r/m2h740zz1i.fsf@gmail.com

Marc Zyngier (19):
  KVM: arm64: Add get_reg_by_id() as a sys_reg_desc retrieving helper
  KVM: arm64: Reorder handling of invariant sysregs from userspace
  KVM: arm64: Introduce generic get_user/set_user helpers for system
    registers
  KVM: arm64: Push checks for 64bit registers into the low-level
    accessors
  KVM: arm64: Consolidate sysreg userspace accesses
  KVM: arm64: Get rid of reg_from/to_user()
  KVM: arm64: vgic-v3: Simplify vgic_v3_has_cpu_sysregs_attr()
  KVM: arm64: vgic-v3: Push user access into
    vgic_v3_cpu_sysregs_uaccess()
  KVM: arm64: vgic-v3: Make the userspace accessors use sysreg API
  KVM: arm64: vgic-v3: Convert userspace accessors over to
    FIELD_GET/FIELD_PREP
  KVM: arm64: vgic-v3: Use u32 to manage the line level from userspace
  KVM: arm64: vgic-v3: Consolidate userspace access for MMIO registers
  KVM: arm64: vgic-v2: Consolidate userspace access for MMIO registers
  KVM: arm64: vgic: Use {get,put}_user() instead of copy_{from.to}_user
  KVM: arm64: vgic-v2: Add helper for legacy dist/cpuif base address
    setting
  KVM: arm64: vgic: Consolidate userspace access for base address
    setting
  KVM: arm64: Get rid of find_reg_by_id()
  KVM: arm64: Descope kvm_arm_sys_reg_{get,set}_reg()
  KVM: arm64: Get rid or outdated comments

 arch/arm64/include/asm/kvm_host.h     |   2 -
 arch/arm64/kvm/arm.c                  |  11 +-
 arch/arm64/kvm/sys_regs.c             | 291 +++++++---------
 arch/arm64/kvm/sys_regs.h             |  18 +-
 arch/arm64/kvm/vgic-sys-reg-v3.c      | 461 +++++++++++++++-----------
 arch/arm64/kvm/vgic/vgic-kvm-device.c | 269 +++++++--------
 arch/arm64/kvm/vgic/vgic-mmio-v3.c    |  10 +-
 arch/arm64/kvm/vgic/vgic-mmio.c       |   6 +-
 arch/arm64/kvm/vgic/vgic-mmio.h       |   4 +-
 arch/arm64/kvm/vgic/vgic.h            |   9 +-
 include/kvm/arm_vgic.h                |   2 +-
 11 files changed, 535 insertions(+), 548 deletions(-)

-- 
2.34.1


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[PATCH 01/19] KVM: arm64: Add get_reg_by_id() as a sys_reg_desc retrieving helper

[Marc Zyngier]

find_reg_by_id() requires a sys_reg_param as input, which most
users provide as a on-stack variable, but don't make any use of
the result.

Provide a helper that doesn't have this requirement and simplify
the callers (all but one).

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c        | 28 +++++++++++++++++-----------
 arch/arm64/kvm/sys_regs.h        |  4 ++++
 arch/arm64/kvm/vgic-sys-reg-v3.c |  8 ++------
 3 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index c06c0477fab5..1f410283c592 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2650,21 +2650,29 @@ const struct sys_reg_desc *find_reg_by_id(u64 id,
 	return find_reg(params, table, num);
 }
 
+const struct sys_reg_desc *get_reg_by_id(u64 id,
+					 const struct sys_reg_desc table[],
+					 unsigned int num)
+{
+	struct sys_reg_params params;
+
+	if (!index_to_params(id, &params))
+		return NULL;
+
+	return find_reg(&params, table, num);
+}
+
 /* Decode an index value, and find the sys_reg_desc entry. */
 static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
 						    u64 id)
 {
 	const struct sys_reg_desc *r;
-	struct sys_reg_params params;
 
 	/* We only do sys_reg for now. */
 	if ((id & KVM_REG_ARM_COPROC_MASK) != KVM_REG_ARM64_SYSREG)
 		return NULL;
 
-	if (!index_to_params(id, &params))
-		return NULL;
-
-	r = find_reg(&params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
+	r = get_reg_by_id(id, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
 
 	/* Not saved in the sys_reg array and not otherwise accessible? */
 	if (r && !(r->reg || r->get_user))
@@ -2723,11 +2731,10 @@ static int reg_to_user(void __user *uaddr, const u64 *val, u64 id)
 
 static int get_invariant_sys_reg(u64 id, void __user *uaddr)
 {
-	struct sys_reg_params params;
 	const struct sys_reg_desc *r;
 
-	r = find_reg_by_id(id, &params, invariant_sys_regs,
-			   ARRAY_SIZE(invariant_sys_regs));
+	r = get_reg_by_id(id, invariant_sys_regs,
+			  ARRAY_SIZE(invariant_sys_regs));
 	if (!r)
 		return -ENOENT;
 
@@ -2736,13 +2743,12 @@ static int get_invariant_sys_reg(u64 id, void __user *uaddr)
 
 static int set_invariant_sys_reg(u64 id, void __user *uaddr)
 {
-	struct sys_reg_params params;
 	const struct sys_reg_desc *r;
 	int err;
 	u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */
 
-	r = find_reg_by_id(id, &params, invariant_sys_regs,
-			   ARRAY_SIZE(invariant_sys_regs));
+	r = get_reg_by_id(id, invariant_sys_regs,
+			  ARRAY_SIZE(invariant_sys_regs));
 	if (!r)
 		return -ENOENT;
 
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index aee8ea054f0d..ce30ed9566ae 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -195,6 +195,10 @@ const struct sys_reg_desc *find_reg_by_id(u64 id,
 					  const struct sys_reg_desc table[],
 					  unsigned int num);
 
+const struct sys_reg_desc *get_reg_by_id(u64 id,
+					 const struct sys_reg_desc table[],
+					 unsigned int num);
+
 #define AA32(_x)	.aarch32_map = AA32_##_x
 #define Op0(_x) 	.Op0 = _x
 #define Op1(_x) 	.Op1 = _x
diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
index 07d5271e9f05..644acda33c7c 100644
--- a/arch/arm64/kvm/vgic-sys-reg-v3.c
+++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
@@ -263,14 +263,10 @@ static const struct sys_reg_desc gic_v3_icc_reg_descs[] = {
 int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, bool is_write, u64 id,
 				u64 *reg)
 {
-	struct sys_reg_params params;
 	u64 sysreg = (id & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
 
-	params.regval = *reg;
-	params.is_write = is_write;
-
-	if (find_reg_by_id(sysreg, &params, gic_v3_icc_reg_descs,
-			      ARRAY_SIZE(gic_v3_icc_reg_descs)))
+	if (get_reg_by_id(sysreg, gic_v3_icc_reg_descs,
+			  ARRAY_SIZE(gic_v3_icc_reg_descs)))
 		return 0;
 
 	return -ENXIO;
-- 
2.34.1


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Re: [PATCH 01/19] KVM: arm64: Add get_reg_by_id() as a sys_reg_desc retrieving helper

[Reiji Watanabe]

Hi Marc,

On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
>
> find_reg_by_id() requires a sys_reg_param as input, which most
> users provide as a on-stack variable, but don't make any use of
> the result.
>
> Provide a helper that doesn't have this requirement and simplify
> the callers (all but one).
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/sys_regs.c        | 28 +++++++++++++++++-----------
>  arch/arm64/kvm/sys_regs.h        |  4 ++++
>  arch/arm64/kvm/vgic-sys-reg-v3.c |  8 ++------
>  3 files changed, 23 insertions(+), 17 deletions(-)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index c06c0477fab5..1f410283c592 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -2650,21 +2650,29 @@ const struct sys_reg_desc *find_reg_by_id(u64 id,
>         return find_reg(params, table, num);
>  }
>
> +const struct sys_reg_desc *get_reg_by_id(u64 id,
> +                                        const struct sys_reg_desc table[],
> +                                        unsigned int num)
> +{
> +       struct sys_reg_params params;
> +
> +       if (!index_to_params(id, &params))
> +               return NULL;
> +
> +       return find_reg(&params, table, num);
> +}

Since all the callers of get_reg_id() specify ARRAY_SIZE(array) for
the 3rd argument, and I think future callers of it are also likely to
do the same, perhaps it might be more convenient if we make get_reg_id()
a wrapper macro like below (and rename "get_reg_by_id()" to
"__get_reg_by_id()") ?

#define get_reg_id(id, table)   __get_reg_id(id, table, ARRAY_SIZE(table))

Thanks,
Reiji


> +
>  /* Decode an index value, and find the sys_reg_desc entry. */
>  static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
>                                                     u64 id)
>  {
>         const struct sys_reg_desc *r;
> -       struct sys_reg_params params;
>
>         /* We only do sys_reg for now. */
>         if ((id & KVM_REG_ARM_COPROC_MASK) != KVM_REG_ARM64_SYSREG)
>                 return NULL;
>
> -       if (!index_to_params(id, &params))
> -               return NULL;
> -
> -       r = find_reg(&params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
> +       r = get_reg_by_id(id, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
>
>         /* Not saved in the sys_reg array and not otherwise accessible? */
>         if (r && !(r->reg || r->get_user))
> @@ -2723,11 +2731,10 @@ static int reg_to_user(void __user *uaddr, const u64 *val, u64 id)
>
>  static int get_invariant_sys_reg(u64 id, void __user *uaddr)
>  {
> -       struct sys_reg_params params;
>         const struct sys_reg_desc *r;
>
> -       r = find_reg_by_id(id, &params, invariant_sys_regs,
> -                          ARRAY_SIZE(invariant_sys_regs));
> +       r = get_reg_by_id(id, invariant_sys_regs,
> +                         ARRAY_SIZE(invariant_sys_regs));
>         if (!r)
>                 return -ENOENT;
>
> @@ -2736,13 +2743,12 @@ static int get_invariant_sys_reg(u64 id, void __user *uaddr)
>
>  static int set_invariant_sys_reg(u64 id, void __user *uaddr)
>  {
> -       struct sys_reg_params params;
>         const struct sys_reg_desc *r;
>         int err;
>         u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */
>
> -       r = find_reg_by_id(id, &params, invariant_sys_regs,
> -                          ARRAY_SIZE(invariant_sys_regs));
> +       r = get_reg_by_id(id, invariant_sys_regs,
> +                         ARRAY_SIZE(invariant_sys_regs));
>         if (!r)
>                 return -ENOENT;
>
> diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
> index aee8ea054f0d..ce30ed9566ae 100644
> --- a/arch/arm64/kvm/sys_regs.h
> +++ b/arch/arm64/kvm/sys_regs.h
> @@ -195,6 +195,10 @@ const struct sys_reg_desc *find_reg_by_id(u64 id,
>                                           const struct sys_reg_desc table[],
>                                           unsigned int num);
>
> +const struct sys_reg_desc *get_reg_by_id(u64 id,
> +                                        const struct sys_reg_desc table[],
> +                                        unsigned int num);
> +
>  #define AA32(_x)       .aarch32_map = AA32_##_x
>  #define Op0(_x)        .Op0 = _x
>  #define Op1(_x)        .Op1 = _x
> diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
> index 07d5271e9f05..644acda33c7c 100644
> --- a/arch/arm64/kvm/vgic-sys-reg-v3.c
> +++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
> @@ -263,14 +263,10 @@ static const struct sys_reg_desc gic_v3_icc_reg_descs[] = {
>  int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, bool is_write, u64 id,
>                                 u64 *reg)
>  {
> -       struct sys_reg_params params;
>         u64 sysreg = (id & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
>
> -       params.regval = *reg;
> -       params.is_write = is_write;
> -
> -       if (find_reg_by_id(sysreg, &params, gic_v3_icc_reg_descs,
> -                             ARRAY_SIZE(gic_v3_icc_reg_descs)))
> +       if (get_reg_by_id(sysreg, gic_v3_icc_reg_descs,
> +                         ARRAY_SIZE(gic_v3_icc_reg_descs)))
>                 return 0;
>
>         return -ENXIO;
> --
> 2.34.1
>
> _______________________________________________
> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

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Re: [PATCH 01/19] KVM: arm64: Add get_reg_by_id() as a sys_reg_desc retrieving helper

[Reiji Watanabe]

On Wed, Jul 6, 2022 at 9:05 PM Reiji Watanabe <reijiw@google.com> wrote:
>
> Hi Marc,
>
> On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
> >
> > find_reg_by_id() requires a sys_reg_param as input, which most
> > users provide as a on-stack variable, but don't make any use of
> > the result.
> >
> > Provide a helper that doesn't have this requirement and simplify
> > the callers (all but one).
> >
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > ---
> >  arch/arm64/kvm/sys_regs.c        | 28 +++++++++++++++++-----------
> >  arch/arm64/kvm/sys_regs.h        |  4 ++++
> >  arch/arm64/kvm/vgic-sys-reg-v3.c |  8 ++------
> >  3 files changed, 23 insertions(+), 17 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> > index c06c0477fab5..1f410283c592 100644
> > --- a/arch/arm64/kvm/sys_regs.c
> > +++ b/arch/arm64/kvm/sys_regs.c
> > @@ -2650,21 +2650,29 @@ const struct sys_reg_desc *find_reg_by_id(u64 id,
> >         return find_reg(params, table, num);
> >  }
> >
> > +const struct sys_reg_desc *get_reg_by_id(u64 id,
> > +                                        const struct sys_reg_desc table[],
> > +                                        unsigned int num)
> > +{
> > +       struct sys_reg_params params;
> > +
> > +       if (!index_to_params(id, &params))
> > +               return NULL;
> > +
> > +       return find_reg(&params, table, num);
> > +}
>
> Since all the callers of get_reg_id() specify ARRAY_SIZE(array) for
> the 3rd argument, and I think future callers of it are also likely to
> do the same, perhaps it might be more convenient if we make get_reg_id()
> a wrapper macro like below (and rename "get_reg_by_id()" to
> "__get_reg_by_id()") ?
>
> #define get_reg_id(id, table)   __get_reg_id(id, table, ARRAY_SIZE(table))

Looking at the following patches, let me withdraw this comment... Instead,

Reviewed-by: Reiji Watanabe <reijiw@google.com>

Thank you,
Reiji


>
> > +
> >  /* Decode an index value, and find the sys_reg_desc entry. */
> >  static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
> >                                                     u64 id)
> >  {
> >         const struct sys_reg_desc *r;
> > -       struct sys_reg_params params;
> >
> >         /* We only do sys_reg for now. */
> >         if ((id & KVM_REG_ARM_COPROC_MASK) != KVM_REG_ARM64_SYSREG)
> >                 return NULL;
> >
> > -       if (!index_to_params(id, &params))
> > -               return NULL;
> > -
> > -       r = find_reg(&params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
> > +       r = get_reg_by_id(id, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
> >
> >         /* Not saved in the sys_reg array and not otherwise accessible? */
> >         if (r && !(r->reg || r->get_user))
> > @@ -2723,11 +2731,10 @@ static int reg_to_user(void __user *uaddr, const u64 *val, u64 id)
> >
> >  static int get_invariant_sys_reg(u64 id, void __user *uaddr)
> >  {
> > -       struct sys_reg_params params;
> >         const struct sys_reg_desc *r;
> >
> > -       r = find_reg_by_id(id, &params, invariant_sys_regs,
> > -                          ARRAY_SIZE(invariant_sys_regs));
> > +       r = get_reg_by_id(id, invariant_sys_regs,
> > +                         ARRAY_SIZE(invariant_sys_regs));
> >         if (!r)
> >                 return -ENOENT;
> >
> > @@ -2736,13 +2743,12 @@ static int get_invariant_sys_reg(u64 id, void __user *uaddr)
> >
> >  static int set_invariant_sys_reg(u64 id, void __user *uaddr)
> >  {
> > -       struct sys_reg_params params;
> >         const struct sys_reg_desc *r;
> >         int err;
> >         u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */
> >
> > -       r = find_reg_by_id(id, &params, invariant_sys_regs,
> > -                          ARRAY_SIZE(invariant_sys_regs));
> > +       r = get_reg_by_id(id, invariant_sys_regs,
> > +                         ARRAY_SIZE(invariant_sys_regs));
> >         if (!r)
> >                 return -ENOENT;
> >
> > diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
> > index aee8ea054f0d..ce30ed9566ae 100644
> > --- a/arch/arm64/kvm/sys_regs.h
> > +++ b/arch/arm64/kvm/sys_regs.h
> > @@ -195,6 +195,10 @@ const struct sys_reg_desc *find_reg_by_id(u64 id,
> >                                           const struct sys_reg_desc table[],
> >                                           unsigned int num);
> >
> > +const struct sys_reg_desc *get_reg_by_id(u64 id,
> > +                                        const struct sys_reg_desc table[],
> > +                                        unsigned int num);
> > +
> >  #define AA32(_x)       .aarch32_map = AA32_##_x
> >  #define Op0(_x)        .Op0 = _x
> >  #define Op1(_x)        .Op1 = _x
> > diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
> > index 07d5271e9f05..644acda33c7c 100644
> > --- a/arch/arm64/kvm/vgic-sys-reg-v3.c
> > +++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
> > @@ -263,14 +263,10 @@ static const struct sys_reg_desc gic_v3_icc_reg_descs[] = {
> >  int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, bool is_write, u64 id,
> >                                 u64 *reg)
> >  {
> > -       struct sys_reg_params params;
> >         u64 sysreg = (id & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
> >
> > -       params.regval = *reg;
> > -       params.is_write = is_write;
> > -
> > -       if (find_reg_by_id(sysreg, &params, gic_v3_icc_reg_descs,
> > -                             ARRAY_SIZE(gic_v3_icc_reg_descs)))
> > +       if (get_reg_by_id(sysreg, gic_v3_icc_reg_descs,
> > +                         ARRAY_SIZE(gic_v3_icc_reg_descs)))
> >                 return 0;
> >
> >         return -ENXIO;
> > --
> > 2.34.1
> >
> > _______________________________________________
> > kvmarm mailing list
> > kvmarm@lists.cs.columbia.edu
> > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

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[PATCH 02/19] KVM: arm64: Reorder handling of invariant sysregs from userspace

[Marc Zyngier]

In order to allow some further refactor of the sysreg helpers,
move the handling of invariant sysreg to occur before we handle
all the other ones.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 1f410283c592..9291cb94c2e4 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2849,6 +2849,7 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
 {
 	const struct sys_reg_desc *r;
 	void __user *uaddr = (void __user *)(unsigned long)reg->addr;
+	int err;
 
 	if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
 		return demux_c15_get(reg->id, uaddr);
@@ -2856,12 +2857,14 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
 	if (KVM_REG_SIZE(reg->id) != sizeof(__u64))
 		return -ENOENT;
 
+	err = get_invariant_sys_reg(reg->id, uaddr);
+	if (err != -ENOENT)
+		return err;
+
 	r = index_to_sys_reg_desc(vcpu, reg->id);
-	if (!r)
-		return get_invariant_sys_reg(reg->id, uaddr);
 
 	/* Check for regs disabled by runtime config */
-	if (sysreg_hidden(vcpu, r))
+	if (!r || sysreg_hidden(vcpu, r))
 		return -ENOENT;
 
 	if (r->get_user)
@@ -2874,6 +2877,7 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
 {
 	const struct sys_reg_desc *r;
 	void __user *uaddr = (void __user *)(unsigned long)reg->addr;
+	int err;
 
 	if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
 		return demux_c15_set(reg->id, uaddr);
@@ -2881,12 +2885,14 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
 	if (KVM_REG_SIZE(reg->id) != sizeof(__u64))
 		return -ENOENT;
 
+	err = set_invariant_sys_reg(reg->id, uaddr);
+	if (err != -ENOENT)
+		return err;
+
 	r = index_to_sys_reg_desc(vcpu, reg->id);
-	if (!r)
-		return set_invariant_sys_reg(reg->id, uaddr);
 
 	/* Check for regs disabled by runtime config */
-	if (sysreg_hidden(vcpu, r))
+	if (!r || sysreg_hidden(vcpu, r))
 		return -ENOENT;
 
 	if (r->set_user)
-- 
2.34.1


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Re: [PATCH 02/19] KVM: arm64: Reorder handling of invariant sysregs from userspace

[Reiji Watanabe]

On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
>
> In order to allow some further refactor of the sysreg helpers,
> move the handling of invariant sysreg to occur before we handle
> all the other ones.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Reiji Watanabe <reijiw@google.com>

Thanks,
Reiji

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[PATCH 03/19] KVM: arm64: Introduce generic get_user/set_user helpers for system registers

[Marc Zyngier]

The userspace access to the system registers is done using helpers
that hardcode the table that is looked up. extract some generic
helpers from this, moving the handling of hidden sysregs into
the core code.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 60 +++++++++++++++++++++++++--------------
 arch/arm64/kvm/sys_regs.h |  6 ++++
 2 files changed, 44 insertions(+), 22 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 9291cb94c2e4..0fbdb21a3600 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2663,8 +2663,10 @@ const struct sys_reg_desc *get_reg_by_id(u64 id,
 }
 
 /* Decode an index value, and find the sys_reg_desc entry. */
-static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
-						    u64 id)
+static const struct sys_reg_desc *
+id_to_sys_reg_desc(struct kvm_vcpu *vcpu, u64 id,
+		   const struct sys_reg_desc table[], unsigned int num)
+
 {
 	const struct sys_reg_desc *r;
 
@@ -2672,10 +2674,10 @@ static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
 	if ((id & KVM_REG_ARM_COPROC_MASK) != KVM_REG_ARM64_SYSREG)
 		return NULL;
 
-	r = get_reg_by_id(id, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
+	r = get_reg_by_id(id, table, num);
 
 	/* Not saved in the sys_reg array and not otherwise accessible? */
-	if (r && !(r->reg || r->get_user))
+	if (r && (!(r->reg || r->get_user) || sysreg_hidden(vcpu, r)))
 		r = NULL;
 
 	return r;
@@ -2845,9 +2847,24 @@ static int demux_c15_set(u64 id, void __user *uaddr)
 	}
 }
 
-int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
+			 const struct sys_reg_desc table[], unsigned int num)
 {
+	void __user *uaddr = (void __user *)(unsigned long)reg->addr;
 	const struct sys_reg_desc *r;
+
+	r = id_to_sys_reg_desc(vcpu, reg->id, table, num);
+	if (!r)
+		return -ENOENT;
+
+	if (r->get_user)
+		return (r->get_user)(vcpu, r, reg, uaddr);
+
+	return reg_to_user(uaddr, &__vcpu_sys_reg(vcpu, r->reg), reg->id);
+}
+
+int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
 	void __user *uaddr = (void __user *)(unsigned long)reg->addr;
 	int err;
 
@@ -2861,21 +2878,28 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
 	if (err != -ENOENT)
 		return err;
 
-	r = index_to_sys_reg_desc(vcpu, reg->id);
+	return kvm_sys_reg_get_user(vcpu, reg,
+				    sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
+}
 
-	/* Check for regs disabled by runtime config */
-	if (!r || sysreg_hidden(vcpu, r))
+int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
+			 const struct sys_reg_desc table[], unsigned int num)
+{
+	void __user *uaddr = (void __user *)(unsigned long)reg->addr;
+	const struct sys_reg_desc *r;
+
+	r = id_to_sys_reg_desc(vcpu, reg->id, table, num);
+	if (!r)
 		return -ENOENT;
 
-	if (r->get_user)
-		return (r->get_user)(vcpu, r, reg, uaddr);
+	if (r->set_user)
+		return (r->set_user)(vcpu, r, reg, uaddr);
 
-	return reg_to_user(uaddr, &__vcpu_sys_reg(vcpu, r->reg), reg->id);
+	return reg_from_user(&__vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
 }
 
 int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 {
-	const struct sys_reg_desc *r;
 	void __user *uaddr = (void __user *)(unsigned long)reg->addr;
 	int err;
 
@@ -2889,16 +2913,8 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
 	if (err != -ENOENT)
 		return err;
 
-	r = index_to_sys_reg_desc(vcpu, reg->id);
-
-	/* Check for regs disabled by runtime config */
-	if (!r || sysreg_hidden(vcpu, r))
-		return -ENOENT;
-
-	if (r->set_user)
-		return (r->set_user)(vcpu, r, reg, uaddr);
-
-	return reg_from_user(&__vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
+	return kvm_sys_reg_set_user(vcpu, reg,
+				    sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
 }
 
 static unsigned int num_demux_regs(void)
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index ce30ed9566ae..4fb6d59e7874 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -199,6 +199,12 @@ const struct sys_reg_desc *get_reg_by_id(u64 id,
 					 const struct sys_reg_desc table[],
 					 unsigned int num);
 
+int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
+			 const struct sys_reg_desc table[], unsigned int num);
+
+int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
+			 const struct sys_reg_desc table[], unsigned int num);
+
 #define AA32(_x)	.aarch32_map = AA32_##_x
 #define Op0(_x) 	.Op0 = _x
 #define Op1(_x) 	.Op1 = _x
-- 
2.34.1


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Re: [PATCH 03/19] KVM: arm64: Introduce generic get_user/set_user helpers for system registers

[Oliver Upton]

On Wed, Jul 06, 2022 at 05:42:48PM +0100, Marc Zyngier wrote:
> The userspace access to the system registers is done using helpers
> that hardcode the table that is looked up. extract some generic
> helpers from this, moving the handling of hidden sysregs into
> the core code.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>

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Re: [PATCH 03/19] KVM: arm64: Introduce generic get_user/set_user helpers for system registers

[Reiji Watanabe]

On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
>
> The userspace access to the system registers is done using helpers
> that hardcode the table that is looked up. extract some generic
> helpers from this, moving the handling of hidden sysregs into
> the core code.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Reiji Watanabe <reijiw@google.com>

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[PATCH 04/19] KVM: arm64: Push checks for 64bit registers into the low-level accessors

[Marc Zyngier]

Make sure the check occurs on every paths where we can pick
a sysreg from userspace, including the GICv3 paths.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0fbdb21a3600..89e7eddea937 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2656,6 +2656,10 @@ const struct sys_reg_desc *get_reg_by_id(u64 id,
 {
 	struct sys_reg_params params;
 
+	/* 64 bit is the only way */
+	if (KVM_REG_SIZE(id) != sizeof(__u64))
+		return NULL;
+
 	if (!index_to_params(id, &params))
 		return NULL;
 
@@ -2871,9 +2875,6 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
 	if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
 		return demux_c15_get(reg->id, uaddr);
 
-	if (KVM_REG_SIZE(reg->id) != sizeof(__u64))
-		return -ENOENT;
-
 	err = get_invariant_sys_reg(reg->id, uaddr);
 	if (err != -ENOENT)
 		return err;
@@ -2906,9 +2907,6 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
 	if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
 		return demux_c15_set(reg->id, uaddr);
 
-	if (KVM_REG_SIZE(reg->id) != sizeof(__u64))
-		return -ENOENT;
-
 	err = set_invariant_sys_reg(reg->id, uaddr);
 	if (err != -ENOENT)
 		return err;
-- 
2.34.1


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Re: [PATCH 04/19] KVM: arm64: Push checks for 64bit registers into the low-level accessors

[Reiji Watanabe]

Hi Marc,

On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
>
> Make sure the check occurs on every paths where we can pick
> a sysreg from userspace, including the GICv3 paths.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/sys_regs.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 0fbdb21a3600..89e7eddea937 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -2656,6 +2656,10 @@ const struct sys_reg_desc *get_reg_by_id(u64 id,
>  {
>         struct sys_reg_params params;
>
> +       /* 64 bit is the only way */
> +       if (KVM_REG_SIZE(id) != sizeof(__u64))
> +               return NULL;

This doesn't seem to be necessary since the equivalent check
is done by index_to_params().

Thank you,
Reiji

> +
>         if (!index_to_params(id, &params))
>                 return NULL;
>
> @@ -2871,9 +2875,6 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
>         if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
>                 return demux_c15_get(reg->id, uaddr);
>
> -       if (KVM_REG_SIZE(reg->id) != sizeof(__u64))
> -               return -ENOENT;
> -
>         err = get_invariant_sys_reg(reg->id, uaddr);
>         if (err != -ENOENT)
>                 return err;
> @@ -2906,9 +2907,6 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
>         if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
>                 return demux_c15_set(reg->id, uaddr);
>
> -       if (KVM_REG_SIZE(reg->id) != sizeof(__u64))
> -               return -ENOENT;
> -
>         err = set_invariant_sys_reg(reg->id, uaddr);
>         if (err != -ENOENT)
>                 return err;
> --
> 2.34.1
>
> _______________________________________________
> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

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Re: [PATCH 04/19] KVM: arm64: Push checks for 64bit registers into the low-level accessors

[Marc Zyngier]

On Fri, 08 Jul 2022 07:13:36 +0100,
Reiji Watanabe <reijiw@google.com> wrote:
> 
> Hi Marc,
> 
> On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
> >
> > Make sure the check occurs on every paths where we can pick
> > a sysreg from userspace, including the GICv3 paths.
> >
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > ---
> >  arch/arm64/kvm/sys_regs.c | 10 ++++------
> >  1 file changed, 4 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> > index 0fbdb21a3600..89e7eddea937 100644
> > --- a/arch/arm64/kvm/sys_regs.c
> > +++ b/arch/arm64/kvm/sys_regs.c
> > @@ -2656,6 +2656,10 @@ const struct sys_reg_desc *get_reg_by_id(u64 id,
> >  {
> >         struct sys_reg_params params;
> >
> > +       /* 64 bit is the only way */
> > +       if (KVM_REG_SIZE(id) != sizeof(__u64))
> > +               return NULL;
> 
> This doesn't seem to be necessary since the equivalent check
> is done by index_to_params().

Ah, well spotted. Amusing how many times we check for the same thing!

I'll simplify the patch and amend the commit message.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

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[PATCH 05/19] KVM: arm64: Consolidate sysreg userspace accesses

[Marc Zyngier]

Until now, the .set_user and .get_user callbacks have to implement
(directly or not) the userspace memory accesses. Although this gives
us maximem flexibility, this is also a maintenance burden, making it
hard to audit, and I'd feel much better if it was all located in
a single place.

So let's do just that, simplifying most of the function signatures
in the process (the callbacks are now only concerned with the
data itself, and not with userspace).

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 162 ++++++++++++++------------------------
 arch/arm64/kvm/sys_regs.h |   4 +-
 2 files changed, 63 insertions(+), 103 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 89e7eddea937..1ce439eed3d8 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -321,16 +321,8 @@ static bool trap_oslsr_el1(struct kvm_vcpu *vcpu,
 }
 
 static int set_oslsr_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-			 const struct kvm_one_reg *reg, void __user *uaddr)
+			 u64 val)
 {
-	u64 id = sys_reg_to_index(rd);
-	u64 val;
-	int err;
-
-	err = reg_from_user(&val, uaddr, id);
-	if (err)
-		return err;
-
 	/*
 	 * The only modifiable bit is the OSLK bit. Refuse the write if
 	 * userspace attempts to change any other bit in the register.
@@ -451,22 +443,16 @@ static bool trap_bvr(struct kvm_vcpu *vcpu,
 }
 
 static int set_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-		const struct kvm_one_reg *reg, void __user *uaddr)
+		   u64 val)
 {
-	__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->CRm];
-
-	if (copy_from_user(r, uaddr, KVM_REG_SIZE(reg->id)) != 0)
-		return -EFAULT;
+	vcpu->arch.vcpu_debug_state.dbg_bvr[rd->CRm] = val;
 	return 0;
 }
 
 static int get_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-	const struct kvm_one_reg *reg, void __user *uaddr)
+		   u64 *val)
 {
-	__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->CRm];
-
-	if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
-		return -EFAULT;
+	*val = vcpu->arch.vcpu_debug_state.dbg_bvr[rd->CRm];
 	return 0;
 }
 
@@ -493,23 +479,16 @@ static bool trap_bcr(struct kvm_vcpu *vcpu,
 }
 
 static int set_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-		const struct kvm_one_reg *reg, void __user *uaddr)
+		   u64 val)
 {
-	__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->CRm];
-
-	if (copy_from_user(r, uaddr, KVM_REG_SIZE(reg->id)) != 0)
-		return -EFAULT;
-
+	vcpu->arch.vcpu_debug_state.dbg_bcr[rd->CRm] = val;
 	return 0;
 }
 
 static int get_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-	const struct kvm_one_reg *reg, void __user *uaddr)
+		   u64 *val)
 {
-	__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->CRm];
-
-	if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
-		return -EFAULT;
+	*val = vcpu->arch.vcpu_debug_state.dbg_bcr[rd->CRm];
 	return 0;
 }
 
@@ -537,22 +516,16 @@ static bool trap_wvr(struct kvm_vcpu *vcpu,
 }
 
 static int set_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-		const struct kvm_one_reg *reg, void __user *uaddr)
+		   u64 val)
 {
-	__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->CRm];
-
-	if (copy_from_user(r, uaddr, KVM_REG_SIZE(reg->id)) != 0)
-		return -EFAULT;
+	vcpu->arch.vcpu_debug_state.dbg_wvr[rd->CRm] = val;
 	return 0;
 }
 
 static int get_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-	const struct kvm_one_reg *reg, void __user *uaddr)
+		   u64 *val)
 {
-	__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->CRm];
-
-	if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
-		return -EFAULT;
+	*val = vcpu->arch.vcpu_debug_state.dbg_wvr[rd->CRm];
 	return 0;
 }
 
@@ -579,22 +552,16 @@ static bool trap_wcr(struct kvm_vcpu *vcpu,
 }
 
 static int set_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-		const struct kvm_one_reg *reg, void __user *uaddr)
+		   u64 val)
 {
-	__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->CRm];
-
-	if (copy_from_user(r, uaddr, KVM_REG_SIZE(reg->id)) != 0)
-		return -EFAULT;
+	vcpu->arch.vcpu_debug_state.dbg_wcr[rd->CRm] = val;
 	return 0;
 }
 
 static int get_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-	const struct kvm_one_reg *reg, void __user *uaddr)
+		   u64 *val)
 {
-	__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->CRm];
-
-	if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
-		return -EFAULT;
+	*val = vcpu->arch.vcpu_debug_state.dbg_wcr[rd->CRm];
 	return 0;
 }
 
@@ -1227,16 +1194,9 @@ static unsigned int sve_visibility(const struct kvm_vcpu *vcpu,
 
 static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
 			       const struct sys_reg_desc *rd,
-			       const struct kvm_one_reg *reg, void __user *uaddr)
+			       u64 val)
 {
-	const u64 id = sys_reg_to_index(rd);
 	u8 csv2, csv3;
-	int err;
-	u64 val;
-
-	err = reg_from_user(&val, uaddr, id);
-	if (err)
-		return err;
 
 	/*
 	 * Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as
@@ -1262,7 +1222,7 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
 		return -EINVAL;
 
 	vcpu->kvm->arch.pfr0_csv2 = csv2;
-	vcpu->kvm->arch.pfr0_csv3 = csv3 ;
+	vcpu->kvm->arch.pfr0_csv3 = csv3;
 
 	return 0;
 }
@@ -1275,27 +1235,17 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
  * to be changed.
  */
 static int __get_id_reg(const struct kvm_vcpu *vcpu,
-			const struct sys_reg_desc *rd, void __user *uaddr,
+			const struct sys_reg_desc *rd, u64 *val,
 			bool raz)
 {
-	const u64 id = sys_reg_to_index(rd);
-	const u64 val = read_id_reg(vcpu, rd, raz);
-
-	return reg_to_user(uaddr, &val, id);
+	*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, void __user *uaddr,
+			const struct sys_reg_desc *rd, u64 val,
 			bool raz)
 {
-	const u64 id = sys_reg_to_index(rd);
-	int err;
-	u64 val;
-
-	err = reg_from_user(&val, uaddr, id);
-	if (err)
-		return err;
-
 	/* This is what we mean by invariant: you can't change it. */
 	if (val != read_id_reg(vcpu, rd, raz))
 		return -EINVAL;
@@ -1304,47 +1254,37 @@ static int __set_id_reg(const struct kvm_vcpu *vcpu,
 }
 
 static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-		      const struct kvm_one_reg *reg, void __user *uaddr)
+		      u64 *val)
 {
 	bool raz = sysreg_visible_as_raz(vcpu, rd);
 
-	return __get_id_reg(vcpu, rd, uaddr, raz);
+	return __get_id_reg(vcpu, rd, val, raz);
 }
 
 static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-		      const struct kvm_one_reg *reg, void __user *uaddr)
+		      u64 val)
 {
 	bool raz = sysreg_visible_as_raz(vcpu, rd);
 
-	return __set_id_reg(vcpu, rd, uaddr, raz);
+	return __set_id_reg(vcpu, rd, val, raz);
 }
 
 static int set_raz_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-			  const struct kvm_one_reg *reg, void __user *uaddr)
+			  u64 val)
 {
-	return __set_id_reg(vcpu, rd, uaddr, true);
+	return __set_id_reg(vcpu, rd, val, true);
 }
 
 static int get_raz_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-		       const struct kvm_one_reg *reg, void __user *uaddr)
+		       u64 *val)
 {
-	const u64 id = sys_reg_to_index(rd);
-	const u64 val = 0;
-
-	return reg_to_user(uaddr, &val, id);
+	*val = 0;
+	return 0;
 }
 
 static int set_wi_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-		      const struct kvm_one_reg *reg, void __user *uaddr)
+		      u64 val)
 {
-	int err;
-	u64 val;
-
-	/* Perform the access even if we are going to ignore the value */
-	err = reg_from_user(&val, uaddr, sys_reg_to_index(rd));
-	if (err)
-		return err;
-
 	return 0;
 }
 
@@ -2854,17 +2794,28 @@ static int demux_c15_set(u64 id, void __user *uaddr)
 int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
 			 const struct sys_reg_desc table[], unsigned int num)
 {
-	void __user *uaddr = (void __user *)(unsigned long)reg->addr;
+	u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
 	const struct sys_reg_desc *r;
+	u64 val;
+	int ret;
 
 	r = id_to_sys_reg_desc(vcpu, reg->id, table, num);
 	if (!r)
 		return -ENOENT;
 
-	if (r->get_user)
-		return (r->get_user)(vcpu, r, reg, uaddr);
+	if (r->get_user) {
+		ret = (r->get_user)(vcpu, r, &val);
+	} else {
+		val = __vcpu_sys_reg(vcpu, r->reg);
+		ret = 0;
+	}
+
+	if (!ret) {
+		if (put_user(val, uaddr))
+			ret = -EFAULT;
+	}
 
-	return reg_to_user(uaddr, &__vcpu_sys_reg(vcpu, r->reg), reg->id);
+	return ret;
 }
 
 int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
@@ -2886,17 +2837,26 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
 int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
 			 const struct sys_reg_desc table[], unsigned int num)
 {
-	void __user *uaddr = (void __user *)(unsigned long)reg->addr;
+	u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
 	const struct sys_reg_desc *r;
+	u64 val;
+	int ret;
+
+	if (get_user(val, uaddr))
+		return -EFAULT;
 
 	r = id_to_sys_reg_desc(vcpu, reg->id, table, num);
 	if (!r)
 		return -ENOENT;
 
-	if (r->set_user)
-		return (r->set_user)(vcpu, r, reg, uaddr);
+	if (r->set_user) {
+		ret = (r->set_user)(vcpu, r, val);
+	} else {
+		__vcpu_sys_reg(vcpu, r->reg) = val;
+		ret = 0;
+	}
 
-	return reg_from_user(&__vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
+	return ret;
 }
 
 int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index 4fb6d59e7874..b8b576a2af2b 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -75,9 +75,9 @@ struct sys_reg_desc {
 
 	/* Custom get/set_user functions, fallback to generic if NULL */
 	int (*get_user)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-			const struct kvm_one_reg *reg, void __user *uaddr);
+			u64 *val);
 	int (*set_user)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-			const struct kvm_one_reg *reg, void __user *uaddr);
+			u64 val);
 
 	/* Return mask of REG_* runtime visibility overrides */
 	unsigned int (*visibility)(const struct kvm_vcpu *vcpu,
-- 
2.34.1


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Re: [PATCH 05/19] KVM: arm64: Consolidate sysreg userspace accesses

[Oliver Upton]

Hi Marc,

On Wed, Jul 06, 2022 at 05:42:50PM +0100, Marc Zyngier wrote:
> Until now, the .set_user and .get_user callbacks have to implement
> (directly or not) the userspace memory accesses. Although this gives
> us maximem flexibility, this is also a maintenance burden, making it

typo: maximum

> hard to audit, and I'd feel much better if it was all located in
> a single place.
> 
> So let's do just that, simplifying most of the function signatures
> in the process (the callbacks are now only concerned with the
> data itself, and not with userspace).

Much cleaner!

> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>

_______________________________________________
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Re: [PATCH 05/19] KVM: arm64: Consolidate sysreg userspace accesses

[Reiji Watanabe]

Hi Marc,

On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
>
> Until now, the .set_user and .get_user callbacks have to implement
> (directly or not) the userspace memory accesses. Although this gives
> us maximem flexibility, this is also a maintenance burden, making it
> hard to audit, and I'd feel much better if it was all located in
> a single place.
>
> So let's do just that, simplifying most of the function signatures
> in the process (the callbacks are now only concerned with the
> data itself, and not with userspace).
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/sys_regs.c | 162 ++++++++++++++------------------------
>  arch/arm64/kvm/sys_regs.h |   4 +-
>  2 files changed, 63 insertions(+), 103 deletions(-)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 89e7eddea937..1ce439eed3d8 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -321,16 +321,8 @@ static bool trap_oslsr_el1(struct kvm_vcpu *vcpu,
>  }
>
>  static int set_oslsr_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -                        const struct kvm_one_reg *reg, void __user *uaddr)
> +                        u64 val)
>  {
> -       u64 id = sys_reg_to_index(rd);
> -       u64 val;
> -       int err;
> -
> -       err = reg_from_user(&val, uaddr, id);
> -       if (err)
> -               return err;
> -
>         /*
>          * The only modifiable bit is the OSLK bit. Refuse the write if
>          * userspace attempts to change any other bit in the register.
> @@ -451,22 +443,16 @@ static bool trap_bvr(struct kvm_vcpu *vcpu,
>  }
>
>  static int set_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -               const struct kvm_one_reg *reg, void __user *uaddr)
> +                  u64 val)
>  {
> -       __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->CRm];
> -
> -       if (copy_from_user(r, uaddr, KVM_REG_SIZE(reg->id)) != 0)
> -               return -EFAULT;
> +       vcpu->arch.vcpu_debug_state.dbg_bvr[rd->CRm] = val;
>         return 0;
>  }
>
>  static int get_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -       const struct kvm_one_reg *reg, void __user *uaddr)
> +                  u64 *val)
>  {
> -       __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->CRm];
> -
> -       if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> -               return -EFAULT;
> +       *val = vcpu->arch.vcpu_debug_state.dbg_bvr[rd->CRm];
>         return 0;
>  }
>
> @@ -493,23 +479,16 @@ static bool trap_bcr(struct kvm_vcpu *vcpu,
>  }
>
>  static int set_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -               const struct kvm_one_reg *reg, void __user *uaddr)
> +                  u64 val)
>  {
> -       __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->CRm];
> -
> -       if (copy_from_user(r, uaddr, KVM_REG_SIZE(reg->id)) != 0)
> -               return -EFAULT;
> -
> +       vcpu->arch.vcpu_debug_state.dbg_bcr[rd->CRm] = val;
>         return 0;
>  }
>
>  static int get_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -       const struct kvm_one_reg *reg, void __user *uaddr)
> +                  u64 *val)
>  {
> -       __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->CRm];
> -
> -       if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> -               return -EFAULT;
> +       *val = vcpu->arch.vcpu_debug_state.dbg_bcr[rd->CRm];
>         return 0;
>  }
>
> @@ -537,22 +516,16 @@ static bool trap_wvr(struct kvm_vcpu *vcpu,
>  }
>
>  static int set_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -               const struct kvm_one_reg *reg, void __user *uaddr)
> +                  u64 val)
>  {
> -       __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->CRm];
> -
> -       if (copy_from_user(r, uaddr, KVM_REG_SIZE(reg->id)) != 0)
> -               return -EFAULT;
> +       vcpu->arch.vcpu_debug_state.dbg_wvr[rd->CRm] = val;
>         return 0;
>  }
>
>  static int get_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -       const struct kvm_one_reg *reg, void __user *uaddr)
> +                  u64 *val)
>  {
> -       __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->CRm];
> -
> -       if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> -               return -EFAULT;
> +       *val = vcpu->arch.vcpu_debug_state.dbg_wvr[rd->CRm];
>         return 0;
>  }
>
> @@ -579,22 +552,16 @@ static bool trap_wcr(struct kvm_vcpu *vcpu,
>  }
>
>  static int set_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -               const struct kvm_one_reg *reg, void __user *uaddr)
> +                  u64 val)
>  {
> -       __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->CRm];
> -
> -       if (copy_from_user(r, uaddr, KVM_REG_SIZE(reg->id)) != 0)
> -               return -EFAULT;
> +       vcpu->arch.vcpu_debug_state.dbg_wcr[rd->CRm] = val;
>         return 0;
>  }
>
>  static int get_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -       const struct kvm_one_reg *reg, void __user *uaddr)
> +                  u64 *val)
>  {
> -       __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->CRm];
> -
> -       if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> -               return -EFAULT;
> +       *val = vcpu->arch.vcpu_debug_state.dbg_wcr[rd->CRm];
>         return 0;
>  }
>
> @@ -1227,16 +1194,9 @@ static unsigned int sve_visibility(const struct kvm_vcpu *vcpu,
>
>  static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
>                                const struct sys_reg_desc *rd,
> -                              const struct kvm_one_reg *reg, void __user *uaddr)
> +                              u64 val)
>  {
> -       const u64 id = sys_reg_to_index(rd);
>         u8 csv2, csv3;
> -       int err;
> -       u64 val;
> -
> -       err = reg_from_user(&val, uaddr, id);
> -       if (err)
> -               return err;
>
>         /*
>          * Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as
> @@ -1262,7 +1222,7 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
>                 return -EINVAL;
>
>         vcpu->kvm->arch.pfr0_csv2 = csv2;
> -       vcpu->kvm->arch.pfr0_csv3 = csv3 ;
> +       vcpu->kvm->arch.pfr0_csv3 = csv3;
>
>         return 0;
>  }
> @@ -1275,27 +1235,17 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
>   * to be changed.
>   */
>  static int __get_id_reg(const struct kvm_vcpu *vcpu,
> -                       const struct sys_reg_desc *rd, void __user *uaddr,
> +                       const struct sys_reg_desc *rd, u64 *val,
>                         bool raz)
>  {
> -       const u64 id = sys_reg_to_index(rd);
> -       const u64 val = read_id_reg(vcpu, rd, raz);
> -
> -       return reg_to_user(uaddr, &val, id);
> +       *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, void __user *uaddr,
> +                       const struct sys_reg_desc *rd, u64 val,
>                         bool raz)
>  {
> -       const u64 id = sys_reg_to_index(rd);
> -       int err;
> -       u64 val;
> -
> -       err = reg_from_user(&val, uaddr, id);
> -       if (err)
> -               return err;
> -
>         /* This is what we mean by invariant: you can't change it. */
>         if (val != read_id_reg(vcpu, rd, raz))
>                 return -EINVAL;
> @@ -1304,47 +1254,37 @@ static int __set_id_reg(const struct kvm_vcpu *vcpu,
>  }
>
>  static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -                     const struct kvm_one_reg *reg, void __user *uaddr)
> +                     u64 *val)
>  {
>         bool raz = sysreg_visible_as_raz(vcpu, rd);
>
> -       return __get_id_reg(vcpu, rd, uaddr, raz);
> +       return __get_id_reg(vcpu, rd, val, raz);
>  }
>
>  static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -                     const struct kvm_one_reg *reg, void __user *uaddr)
> +                     u64 val)
>  {
>         bool raz = sysreg_visible_as_raz(vcpu, rd);
>
> -       return __set_id_reg(vcpu, rd, uaddr, raz);
> +       return __set_id_reg(vcpu, rd, val, raz);
>  }
>
>  static int set_raz_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -                         const struct kvm_one_reg *reg, void __user *uaddr)
> +                         u64 val)
>  {
> -       return __set_id_reg(vcpu, rd, uaddr, true);
> +       return __set_id_reg(vcpu, rd, val, true);
>  }
>
>  static int get_raz_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -                      const struct kvm_one_reg *reg, void __user *uaddr)
> +                      u64 *val)
>  {
> -       const u64 id = sys_reg_to_index(rd);
> -       const u64 val = 0;
> -
> -       return reg_to_user(uaddr, &val, id);
> +       *val = 0;
> +       return 0;
>  }
>
>  static int set_wi_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -                     const struct kvm_one_reg *reg, void __user *uaddr)
> +                     u64 val)
>  {
> -       int err;
> -       u64 val;
> -
> -       /* Perform the access even if we are going to ignore the value */
> -       err = reg_from_user(&val, uaddr, sys_reg_to_index(rd));
> -       if (err)
> -               return err;
> -
>         return 0;
>  }
>
> @@ -2854,17 +2794,28 @@ static int demux_c15_set(u64 id, void __user *uaddr)
>  int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
>                          const struct sys_reg_desc table[], unsigned int num)
>  {
> -       void __user *uaddr = (void __user *)(unsigned long)reg->addr;
> +       u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
>         const struct sys_reg_desc *r;
> +       u64 val;
> +       int ret;
>
>         r = id_to_sys_reg_desc(vcpu, reg->id, table, num);
>         if (!r)
>                 return -ENOENT;
>
> -       if (r->get_user)
> -               return (r->get_user)(vcpu, r, reg, uaddr);
> +       if (r->get_user) {
> +               ret = (r->get_user)(vcpu, r, &val);
> +       } else {
> +               val = __vcpu_sys_reg(vcpu, r->reg);
> +               ret = 0;
> +       }
> +
> +       if (!ret) {
> +               if (put_user(val, uaddr))
> +                       ret = -EFAULT;

Nit: Since put_user() returns -EFAULT when it fails,
we can simply set 'ret' to the return value from put_user().
(same for get_user())

Reviewed-by: Reiji Watanabe <reijiw@google.com>

I like this fix!

Thank you,
Reiji

> +       }
>
> -       return reg_to_user(uaddr, &__vcpu_sys_reg(vcpu, r->reg), reg->id);
> +       return ret;
>  }
>
>  int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> @@ -2886,17 +2837,26 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
>  int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
>                          const struct sys_reg_desc table[], unsigned int num)
>  {
> -       void __user *uaddr = (void __user *)(unsigned long)reg->addr;
> +       u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
>         const struct sys_reg_desc *r;
> +       u64 val;
> +       int ret;
> +
> +       if (get_user(val, uaddr))
> +               return -EFAULT;
>
>         r = id_to_sys_reg_desc(vcpu, reg->id, table, num);
>         if (!r)
>                 return -ENOENT;
>
> -       if (r->set_user)
> -               return (r->set_user)(vcpu, r, reg, uaddr);
> +       if (r->set_user) {
> +               ret = (r->set_user)(vcpu, r, val);
> +       } else {
> +               __vcpu_sys_reg(vcpu, r->reg) = val;
> +               ret = 0;
> +       }
>
> -       return reg_from_user(&__vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
> +       return ret;
>  }
>
>  int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
> index 4fb6d59e7874..b8b576a2af2b 100644
> --- a/arch/arm64/kvm/sys_regs.h
> +++ b/arch/arm64/kvm/sys_regs.h
> @@ -75,9 +75,9 @@ struct sys_reg_desc {
>
>         /* Custom get/set_user functions, fallback to generic if NULL */
>         int (*get_user)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -                       const struct kvm_one_reg *reg, void __user *uaddr);
> +                       u64 *val);
>         int (*set_user)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> -                       const struct kvm_one_reg *reg, void __user *uaddr);
> +                       u64 val);
>
>         /* Return mask of REG_* runtime visibility overrides */
>         unsigned int (*visibility)(const struct kvm_vcpu *vcpu,
> --
> 2.34.1
>
> _______________________________________________
> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

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Re: [PATCH 05/19] KVM: arm64: Consolidate sysreg userspace accesses

[Marc Zyngier]

Hi Reiji,

On Sat, 09 Jul 2022 07:55:08 +0100,
Reiji Watanabe <reijiw@google.com> wrote:
> 
> Hi Marc,

[...]

> > @@ -2854,17 +2794,28 @@ static int demux_c15_set(u64 id, void __user *uaddr)
> >  int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
> >                          const struct sys_reg_desc table[], unsigned int num)
> >  {
> > -       void __user *uaddr = (void __user *)(unsigned long)reg->addr;
> > +       u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
> >         const struct sys_reg_desc *r;
> > +       u64 val;
> > +       int ret;
> >
> >         r = id_to_sys_reg_desc(vcpu, reg->id, table, num);
> >         if (!r)
> >                 return -ENOENT;
> >
> > -       if (r->get_user)
> > -               return (r->get_user)(vcpu, r, reg, uaddr);
> > +       if (r->get_user) {
> > +               ret = (r->get_user)(vcpu, r, &val);
> > +       } else {
> > +               val = __vcpu_sys_reg(vcpu, r->reg);
> > +               ret = 0;
> > +       }
> > +
> > +       if (!ret) {
> > +               if (put_user(val, uaddr))
> > +                       ret = -EFAULT;
> 
> Nit: Since put_user() returns -EFAULT when it fails,
> we can simply set 'ret' to the return value from put_user().

Indeed. I've now reworked all the instances of this that survive the
incremental rework. Thanks for the suggestion.

> (same for get_user())

This one is a harder sell, as get_user() usually occurs at the
beginning of the function, without a preexisting error context.

> 
> Reviewed-by: Reiji Watanabe <reijiw@google.com>
> 
> I like this fix!

Thanks!

	M.

-- 
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[PATCH 06/19] KVM: arm64: Get rid of reg_from/to_user()

[Marc Zyngier]

These helpers are only used by the invariant stuff now, and while
they pretend to support non-64bit registers, this only serves as
a way to scare the casual reviewer...

Replace these helpers with our good friends get/put_user(), and
don't look back.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 33 +++++++++------------------------
 1 file changed, 9 insertions(+), 24 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 1ce439eed3d8..b66be9df7a02 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -44,8 +44,6 @@
  * 64bit interface.
  */
 
-static int reg_from_user(u64 *val, const void __user *uaddr, u64 id);
-static int reg_to_user(void __user *uaddr, const u64 *val, u64 id);
 static u64 sys_reg_to_index(const struct sys_reg_desc *reg);
 
 static bool read_from_write_only(struct kvm_vcpu *vcpu,
@@ -2661,21 +2659,7 @@ static struct sys_reg_desc invariant_sys_regs[] = {
 	{ SYS_DESC(SYS_CTR_EL0), NULL, get_ctr_el0 },
 };
 
-static int reg_from_user(u64 *val, const void __user *uaddr, u64 id)
-{
-	if (copy_from_user(val, uaddr, KVM_REG_SIZE(id)) != 0)
-		return -EFAULT;
-	return 0;
-}
-
-static int reg_to_user(void __user *uaddr, const u64 *val, u64 id)
-{
-	if (copy_to_user(uaddr, val, KVM_REG_SIZE(id)) != 0)
-		return -EFAULT;
-	return 0;
-}
-
-static int get_invariant_sys_reg(u64 id, void __user *uaddr)
+static int get_invariant_sys_reg(u64 id, u64 __user *uaddr)
 {
 	const struct sys_reg_desc *r;
 
@@ -2684,23 +2668,24 @@ static int get_invariant_sys_reg(u64 id, void __user *uaddr)
 	if (!r)
 		return -ENOENT;
 
-	return reg_to_user(uaddr, &r->val, id);
+	if (put_user(r->val, uaddr))
+		return -EFAULT;
+
+	return 0;
 }
 
-static int set_invariant_sys_reg(u64 id, void __user *uaddr)
+static int set_invariant_sys_reg(u64 id, u64 __user *uaddr)
 {
 	const struct sys_reg_desc *r;
-	int err;
-	u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */
+	u64 val;
 
 	r = get_reg_by_id(id, invariant_sys_regs,
 			  ARRAY_SIZE(invariant_sys_regs));
 	if (!r)
 		return -ENOENT;
 
-	err = reg_from_user(&val, uaddr, id);
-	if (err)
-		return err;
+	if (get_user(val, uaddr))
+		return -EFAULT;
 
 	/* This is what we mean by invariant: you can't change it. */
 	if (r->val != val)
-- 
2.34.1


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Re: [PATCH 06/19] KVM: arm64: Get rid of reg_from/to_user()

[Oliver Upton]

On Wed, Jul 06, 2022 at 05:42:51PM +0100, Marc Zyngier wrote:
> These helpers are only used by the invariant stuff now, and while
> they pretend to support non-64bit registers, this only serves as
> a way to scare the casual reviewer...
> 
> Replace these helpers with our good friends get/put_user(), and
> don't look back.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>

> ---
>  arch/arm64/kvm/sys_regs.c | 33 +++++++++------------------------
>  1 file changed, 9 insertions(+), 24 deletions(-)
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 1ce439eed3d8..b66be9df7a02 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -44,8 +44,6 @@
>   * 64bit interface.
>   */
>  
> -static int reg_from_user(u64 *val, const void __user *uaddr, u64 id);
> -static int reg_to_user(void __user *uaddr, const u64 *val, u64 id);
>  static u64 sys_reg_to_index(const struct sys_reg_desc *reg);
>  
>  static bool read_from_write_only(struct kvm_vcpu *vcpu,
> @@ -2661,21 +2659,7 @@ static struct sys_reg_desc invariant_sys_regs[] = {
>  	{ SYS_DESC(SYS_CTR_EL0), NULL, get_ctr_el0 },
>  };
>  
> -static int reg_from_user(u64 *val, const void __user *uaddr, u64 id)
> -{
> -	if (copy_from_user(val, uaddr, KVM_REG_SIZE(id)) != 0)
> -		return -EFAULT;
> -	return 0;
> -}
> -
> -static int reg_to_user(void __user *uaddr, const u64 *val, u64 id)
> -{
> -	if (copy_to_user(uaddr, val, KVM_REG_SIZE(id)) != 0)
> -		return -EFAULT;
> -	return 0;
> -}
> -
> -static int get_invariant_sys_reg(u64 id, void __user *uaddr)
> +static int get_invariant_sys_reg(u64 id, u64 __user *uaddr)
>  {
>  	const struct sys_reg_desc *r;
>  
> @@ -2684,23 +2668,24 @@ static int get_invariant_sys_reg(u64 id, void __user *uaddr)
>  	if (!r)
>  		return -ENOENT;
>  
> -	return reg_to_user(uaddr, &r->val, id);
> +	if (put_user(r->val, uaddr))
> +		return -EFAULT;
> +
> +	return 0;
>  }
>  
> -static int set_invariant_sys_reg(u64 id, void __user *uaddr)
> +static int set_invariant_sys_reg(u64 id, u64 __user *uaddr)
>  {
>  	const struct sys_reg_desc *r;
> -	int err;
> -	u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */
> +	u64 val;
>  
>  	r = get_reg_by_id(id, invariant_sys_regs,
>  			  ARRAY_SIZE(invariant_sys_regs));
>  	if (!r)
>  		return -ENOENT;
>  
> -	err = reg_from_user(&val, uaddr, id);
> -	if (err)
> -		return err;
> +	if (get_user(val, uaddr))
> +		return -EFAULT;
>  
>  	/* This is what we mean by invariant: you can't change it. */
>  	if (r->val != val)
> -- 
> 2.34.1
> 

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Re: [PATCH 06/19] KVM: arm64: Get rid of reg_from/to_user()

[Reiji Watanabe]

On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
>
> These helpers are only used by the invariant stuff now, and while
> they pretend to support non-64bit registers, this only serves as
> a way to scare the casual reviewer...
>
> Replace these helpers with our good friends get/put_user(), and
> don't look back.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Reiji Watanabe <reijiw@google.com>

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[PATCH 07/19] KVM: arm64: vgic-v3: Simplify vgic_v3_has_cpu_sysregs_attr()

[Marc Zyngier]

Finding out whether a sysreg exists has little to do with that
register being accessed, so drop the is_write parameter.

Also, the reg pointer is completely unused, and we're better off
just passing the attr pointer to the function.

This result in a small cleanup of the calling site, with a new
helper converting the vGIC view of a sysreg into the canonical
one (this is purely cosmetic, as the encoding is the same).

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic-sys-reg-v3.c   | 14 ++++++++++----
 arch/arm64/kvm/vgic/vgic-mmio-v3.c |  8 ++------
 arch/arm64/kvm/vgic/vgic.h         |  3 +--
 3 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
index 644acda33c7c..85a5e1d15e9f 100644
--- a/arch/arm64/kvm/vgic-sys-reg-v3.c
+++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
@@ -260,12 +260,18 @@ static const struct sys_reg_desc gic_v3_icc_reg_descs[] = {
 	{ SYS_DESC(SYS_ICC_IGRPEN1_EL1), access_gic_grpen1 },
 };
 
-int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, bool is_write, u64 id,
-				u64 *reg)
+static u64 attr_to_id(u64 attr)
 {
-	u64 sysreg = (id & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
+	return ARM64_SYS_REG(FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_OP0_MASK, attr),
+			     FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_OP1_MASK, attr),
+			     FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_CRN_MASK, attr),
+			     FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_CRM_MASK, attr),
+			     FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_OP2_MASK, attr));
+}
 
-	if (get_reg_by_id(sysreg, gic_v3_icc_reg_descs,
+int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+	if (get_reg_by_id(attr_to_id(attr->attr), gic_v3_icc_reg_descs,
 			  ARRAY_SIZE(gic_v3_icc_reg_descs)))
 		return 0;
 
diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
index f15e29cc63ce..a2ff73899976 100644
--- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
@@ -986,12 +986,8 @@ int vgic_v3_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
 		iodev.base_addr = 0;
 		break;
 	}
-	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS: {
-		u64 reg, id;
-
-		id = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_INSTR_MASK);
-		return vgic_v3_has_cpu_sysregs_attr(vcpu, 0, id, &reg);
-	}
+	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
+		return vgic_v3_has_cpu_sysregs_attr(vcpu, attr);
 	default:
 		return -ENXIO;
 	}
diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h
index 4c6bdd321faa..ffc2d3c81b28 100644
--- a/arch/arm64/kvm/vgic/vgic.h
+++ b/arch/arm64/kvm/vgic/vgic.h
@@ -247,8 +247,7 @@ int vgic_v3_redist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 			 int offset, u32 *val);
 int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 			 u64 id, u64 *val);
-int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, bool is_write, u64 id,
-				u64 *reg);
+int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
 int vgic_v3_line_level_info_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 				    u32 intid, u64 *val);
 int kvm_register_vgic_device(unsigned long type);
-- 
2.34.1


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Re: [PATCH 07/19] KVM: arm64: vgic-v3: Simplify vgic_v3_has_cpu_sysregs_attr()

[Oliver Upton]

On Wed, Jul 06, 2022 at 05:42:52PM +0100, Marc Zyngier wrote:
> Finding out whether a sysreg exists has little to do with that
> register being accessed, so drop the is_write parameter.
> 
> Also, the reg pointer is completely unused, and we're better off
> just passing the attr pointer to the function.
> 
> This result in a small cleanup of the calling site, with a new
> helper converting the vGIC view of a sysreg into the canonical
> one (this is purely cosmetic, as the encoding is the same).
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>

> ---
>  arch/arm64/kvm/vgic-sys-reg-v3.c   | 14 ++++++++++----
>  arch/arm64/kvm/vgic/vgic-mmio-v3.c |  8 ++------
>  arch/arm64/kvm/vgic/vgic.h         |  3 +--
>  3 files changed, 13 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
> index 644acda33c7c..85a5e1d15e9f 100644
> --- a/arch/arm64/kvm/vgic-sys-reg-v3.c
> +++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
> @@ -260,12 +260,18 @@ static const struct sys_reg_desc gic_v3_icc_reg_descs[] = {
>  	{ SYS_DESC(SYS_ICC_IGRPEN1_EL1), access_gic_grpen1 },
>  };
>  
> -int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, bool is_write, u64 id,
> -				u64 *reg)
> +static u64 attr_to_id(u64 attr)
>  {
> -	u64 sysreg = (id & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
> +	return ARM64_SYS_REG(FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_OP0_MASK, attr),
> +			     FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_OP1_MASK, attr),
> +			     FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_CRN_MASK, attr),
> +			     FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_CRM_MASK, attr),
> +			     FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_OP2_MASK, attr));
> +}
>  
> -	if (get_reg_by_id(sysreg, gic_v3_icc_reg_descs,
> +int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
> +{
> +	if (get_reg_by_id(attr_to_id(attr->attr), gic_v3_icc_reg_descs,
>  			  ARRAY_SIZE(gic_v3_icc_reg_descs)))
>  		return 0;
>  
> diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
> index f15e29cc63ce..a2ff73899976 100644
> --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c
> +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
> @@ -986,12 +986,8 @@ int vgic_v3_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
>  		iodev.base_addr = 0;
>  		break;
>  	}
> -	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS: {
> -		u64 reg, id;
> -
> -		id = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_INSTR_MASK);
> -		return vgic_v3_has_cpu_sysregs_attr(vcpu, 0, id, &reg);
> -	}
> +	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
> +		return vgic_v3_has_cpu_sysregs_attr(vcpu, attr);
>  	default:
>  		return -ENXIO;
>  	}
> diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h
> index 4c6bdd321faa..ffc2d3c81b28 100644
> --- a/arch/arm64/kvm/vgic/vgic.h
> +++ b/arch/arm64/kvm/vgic/vgic.h
> @@ -247,8 +247,7 @@ int vgic_v3_redist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
>  			 int offset, u32 *val);
>  int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write,
>  			 u64 id, u64 *val);
> -int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, bool is_write, u64 id,
> -				u64 *reg);
> +int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
>  int vgic_v3_line_level_info_uaccess(struct kvm_vcpu *vcpu, bool is_write,
>  				    u32 intid, u64 *val);
>  int kvm_register_vgic_device(unsigned long type);
> -- 
> 2.34.1
> 

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Re: [PATCH 07/19] KVM: arm64: vgic-v3: Simplify vgic_v3_has_cpu_sysregs_attr()

[Reiji Watanabe]

On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
>
> Finding out whether a sysreg exists has little to do with that
> register being accessed, so drop the is_write parameter.
>
> Also, the reg pointer is completely unused, and we're better off
> just passing the attr pointer to the function.
>
> This result in a small cleanup of the calling site, with a new
> helper converting the vGIC view of a sysreg into the canonical
> one (this is purely cosmetic, as the encoding is the same).
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Reiji Watanabe <reijiw@google.com>

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[PATCH 08/19] KVM: arm64: vgic-v3: Push user access into vgic_v3_cpu_sysregs_uaccess()

[Marc Zyngier]

In order to start making the vgic sysreg access from userspace
similar to all the other sysregs, push the userspace memory
access one level down into vgic_v3_cpu_sysregs_uaccess().

The next step will be to rely on the sysreg infrastructure
to perform this task.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic-sys-reg-v3.c      | 22 +++++++++++++------
 arch/arm64/kvm/vgic/vgic-kvm-device.c | 31 ++++++---------------------
 arch/arm64/kvm/vgic/vgic.h            |  4 ++--
 3 files changed, 23 insertions(+), 34 deletions(-)

diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
index 85a5e1d15e9f..8c56e285fde9 100644
--- a/arch/arm64/kvm/vgic-sys-reg-v3.c
+++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
@@ -278,15 +278,21 @@ int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *
 	return -ENXIO;
 }
 
-int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write, u64 id,
-				u64 *reg)
+int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu,
+				struct kvm_device_attr *attr,
+				bool is_write)
 {
+	u64 __user *uaddr = (u64 __user *)(long)attr->addr;
 	struct sys_reg_params params;
 	const struct sys_reg_desc *r;
-	u64 sysreg = (id & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
+	u64 sysreg;
 
-	if (is_write)
-		params.regval = *reg;
+	sysreg = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
+
+	if (is_write) {
+		if (get_user(params.regval, uaddr))
+			return -EFAULT;
+	}
 	params.is_write = is_write;
 
 	r = find_reg_by_id(sysreg, &params, gic_v3_icc_reg_descs,
@@ -297,8 +303,10 @@ int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write, u64 id,
 	if (!r->access(vcpu, &params, r))
 		return -EINVAL;
 
-	if (!is_write)
-		*reg = params.regval;
+	if (!is_write) {
+		if (put_user(params.regval, uaddr))
+			return -EFAULT;
+	}
 
 	return 0;
 }
diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
index c6d52a1fd9c8..d8269300632d 100644
--- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
+++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
@@ -561,14 +561,9 @@ static int vgic_v3_attr_regs_access(struct kvm_device *dev,
 		if (!is_write)
 			*reg = tmp32;
 		break;
-	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS: {
-		u64 regid;
-
-		regid = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_INSTR_MASK);
-		ret = vgic_v3_cpu_sysregs_uaccess(vcpu, is_write,
-						  regid, reg);
+	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
+		ret = vgic_v3_cpu_sysregs_uaccess(vcpu, attr, is_write);
 		break;
-	}
 	case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO: {
 		unsigned int info, intid;
 
@@ -617,15 +612,8 @@ static int vgic_v3_set_attr(struct kvm_device *dev,
 		reg = tmp32;
 		return vgic_v3_attr_regs_access(dev, attr, &reg, true);
 	}
-	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS: {
-		u64 __user *uaddr = (u64 __user *)(long)attr->addr;
-		u64 reg;
-
-		if (get_user(reg, uaddr))
-			return -EFAULT;
-
-		return vgic_v3_attr_regs_access(dev, attr, &reg, true);
-	}
+	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
+		return vgic_v3_attr_regs_access(dev, attr, NULL, true);
 	case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO: {
 		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
 		u64 reg;
@@ -681,15 +669,8 @@ static int vgic_v3_get_attr(struct kvm_device *dev,
 		tmp32 = reg;
 		return put_user(tmp32, uaddr);
 	}
-	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS: {
-		u64 __user *uaddr = (u64 __user *)(long)attr->addr;
-		u64 reg;
-
-		ret = vgic_v3_attr_regs_access(dev, attr, &reg, false);
-		if (ret)
-			return ret;
-		return put_user(reg, uaddr);
-	}
+	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
+		return vgic_v3_attr_regs_access(dev, attr, NULL, false);
 	case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO: {
 		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
 		u64 reg;
diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h
index ffc2d3c81b28..c23118467a35 100644
--- a/arch/arm64/kvm/vgic/vgic.h
+++ b/arch/arm64/kvm/vgic/vgic.h
@@ -245,8 +245,8 @@ int vgic_v3_dist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 			 int offset, u32 *val);
 int vgic_v3_redist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 			 int offset, u32 *val);
-int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write,
-			 u64 id, u64 *val);
+int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu,
+				struct kvm_device_attr *attr, bool is_write);
 int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
 int vgic_v3_line_level_info_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 				    u32 intid, u64 *val);
-- 
2.34.1


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Re: [PATCH 08/19] KVM: arm64: vgic-v3: Push user access into vgic_v3_cpu_sysregs_uaccess()

[Reiji Watanabe]

Hi Marc,

On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
>
> In order to start making the vgic sysreg access from userspace
> similar to all the other sysregs, push the userspace memory
> access one level down into vgic_v3_cpu_sysregs_uaccess().
>
> The next step will be to rely on the sysreg infrastructure
> to perform this task.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/vgic-sys-reg-v3.c      | 22 +++++++++++++------
>  arch/arm64/kvm/vgic/vgic-kvm-device.c | 31 ++++++---------------------
>  arch/arm64/kvm/vgic/vgic.h            |  4 ++--
>  3 files changed, 23 insertions(+), 34 deletions(-)
>
> diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
> index 85a5e1d15e9f..8c56e285fde9 100644
> --- a/arch/arm64/kvm/vgic-sys-reg-v3.c
> +++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
> @@ -278,15 +278,21 @@ int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *
>         return -ENXIO;
>  }
>
> -int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write, u64 id,
> -                               u64 *reg)
> +int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu,
> +                               struct kvm_device_attr *attr,
> +                               bool is_write)
>  {
> +       u64 __user *uaddr = (u64 __user *)(long)attr->addr;
>         struct sys_reg_params params;
>         const struct sys_reg_desc *r;
> -       u64 sysreg = (id & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
> +       u64 sysreg;
>
> -       if (is_write)
> -               params.regval = *reg;
> +       sysreg = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;

Why don't you use attr_to_id() here ?


> +
> +       if (is_write) {
> +               if (get_user(params.regval, uaddr))
> +                       return -EFAULT;
> +       }
>         params.is_write = is_write;
>
>         r = find_reg_by_id(sysreg, &params, gic_v3_icc_reg_descs,
> @@ -297,8 +303,10 @@ int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write, u64 id,
>         if (!r->access(vcpu, &params, r))
>                 return -EINVAL;
>
> -       if (!is_write)
> -               *reg = params.regval;
> +       if (!is_write) {
> +               if (put_user(params.regval, uaddr))
> +                       return -EFAULT;
> +       }
>
>         return 0;
>  }
> diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> index c6d52a1fd9c8..d8269300632d 100644
> --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
> +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> @@ -561,14 +561,9 @@ static int vgic_v3_attr_regs_access(struct kvm_device *dev,
>                 if (!is_write)
>                         *reg = tmp32;
>                 break;
> -       case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS: {
> -               u64 regid;
> -
> -               regid = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_INSTR_MASK);
> -               ret = vgic_v3_cpu_sysregs_uaccess(vcpu, is_write,
> -                                                 regid, reg);
> +       case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
> +               ret = vgic_v3_cpu_sysregs_uaccess(vcpu, attr, is_write);

Nit: Since @reg that is passed to vgic_v3_attr_regs_access() will be NULL
for KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS, I think it would be more clear
if you could update the comment for vgic_v3_attr_regs_access accordingly.

----
/*
 * vgic_v3_attr_regs_access - allows user space to access VGIC v3 state
 *
 * @dev:      kvm device handle
 * @attr:     kvm device attribute
 * @reg:      address the value is read or written
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * @is_write: true if userspace is writing a register
 */
static int vgic_v3_attr_regs_access(struct kvm_device *dev,
                                    struct kvm_device_attr *attr,
                                    u64 *reg, bool is_write)
----

Thank you,
Reiji


>                 break;
> -       }
>         case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO: {
>                 unsigned int info, intid;
>
> @@ -617,15 +612,8 @@ static int vgic_v3_set_attr(struct kvm_device *dev,
>                 reg = tmp32;
>                 return vgic_v3_attr_regs_access(dev, attr, &reg, true);
>         }
> -       case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS: {
> -               u64 __user *uaddr = (u64 __user *)(long)attr->addr;
> -               u64 reg;
> -
> -               if (get_user(reg, uaddr))
> -                       return -EFAULT;
> -
> -               return vgic_v3_attr_regs_access(dev, attr, &reg, true);
> -       }
> +       case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
> +               return vgic_v3_attr_regs_access(dev, attr, NULL, true);
>         case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO: {
>                 u32 __user *uaddr = (u32 __user *)(long)attr->addr;
>                 u64 reg;
> @@ -681,15 +669,8 @@ static int vgic_v3_get_attr(struct kvm_device *dev,
>                 tmp32 = reg;
>                 return put_user(tmp32, uaddr);
>         }
> -       case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS: {
> -               u64 __user *uaddr = (u64 __user *)(long)attr->addr;
> -               u64 reg;
> -
> -               ret = vgic_v3_attr_regs_access(dev, attr, &reg, false);
> -               if (ret)
> -                       return ret;
> -               return put_user(reg, uaddr);
> -       }
> +       case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
> +               return vgic_v3_attr_regs_access(dev, attr, NULL, false);
>         case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO: {
>                 u32 __user *uaddr = (u32 __user *)(long)attr->addr;
>                 u64 reg;
> diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h
> index ffc2d3c81b28..c23118467a35 100644
> --- a/arch/arm64/kvm/vgic/vgic.h
> +++ b/arch/arm64/kvm/vgic/vgic.h
> @@ -245,8 +245,8 @@ int vgic_v3_dist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
>                          int offset, u32 *val);
>  int vgic_v3_redist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
>                          int offset, u32 *val);
> -int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write,
> -                        u64 id, u64 *val);
> +int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu,
> +                               struct kvm_device_attr *attr, bool is_write);
>  int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
>  int vgic_v3_line_level_info_uaccess(struct kvm_vcpu *vcpu, bool is_write,
>                                     u32 intid, u64 *val);
> --
> 2.34.1
>
> _______________________________________________
> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

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Re: [PATCH 08/19] KVM: arm64: vgic-v3: Push user access into vgic_v3_cpu_sysregs_uaccess()

[Marc Zyngier]

Hi Reiji,

On Tue, 12 Jul 2022 07:11:39 +0100,
Reiji Watanabe <reijiw@google.com> wrote:
> 
> Hi Marc,
> 
> On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
> >
> > In order to start making the vgic sysreg access from userspace
> > similar to all the other sysregs, push the userspace memory
> > access one level down into vgic_v3_cpu_sysregs_uaccess().
> >
> > The next step will be to rely on the sysreg infrastructure
> > to perform this task.
> >
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > ---
> >  arch/arm64/kvm/vgic-sys-reg-v3.c      | 22 +++++++++++++------
> >  arch/arm64/kvm/vgic/vgic-kvm-device.c | 31 ++++++---------------------
> >  arch/arm64/kvm/vgic/vgic.h            |  4 ++--
> >  3 files changed, 23 insertions(+), 34 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
> > index 85a5e1d15e9f..8c56e285fde9 100644
> > --- a/arch/arm64/kvm/vgic-sys-reg-v3.c
> > +++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
> > @@ -278,15 +278,21 @@ int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *
> >         return -ENXIO;
> >  }
> >
> > -int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write, u64 id,
> > -                               u64 *reg)
> > +int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu,
> > +                               struct kvm_device_attr *attr,
> > +                               bool is_write)
> >  {
> > +       u64 __user *uaddr = (u64 __user *)(long)attr->addr;
> >         struct sys_reg_params params;
> >         const struct sys_reg_desc *r;
> > -       u64 sysreg = (id & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
> > +       u64 sysreg;
> >
> > -       if (is_write)
> > -               params.regval = *reg;
> > +       sysreg = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
> 
> Why don't you use attr_to_id() here ?

This actually happens in the following patch. Happy to move the change
here though.

> 
> 
> > +
> > +       if (is_write) {
> > +               if (get_user(params.regval, uaddr))
> > +                       return -EFAULT;
> > +       }
> >         params.is_write = is_write;
> >
> >         r = find_reg_by_id(sysreg, &params, gic_v3_icc_reg_descs,
> > @@ -297,8 +303,10 @@ int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write, u64 id,
> >         if (!r->access(vcpu, &params, r))
> >                 return -EINVAL;
> >
> > -       if (!is_write)
> > -               *reg = params.regval;
> > +       if (!is_write) {
> > +               if (put_user(params.regval, uaddr))
> > +                       return -EFAULT;
> > +       }
> >
> >         return 0;
> >  }
> > diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > index c6d52a1fd9c8..d8269300632d 100644
> > --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > @@ -561,14 +561,9 @@ static int vgic_v3_attr_regs_access(struct kvm_device *dev,
> >                 if (!is_write)
> >                         *reg = tmp32;
> >                 break;
> > -       case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS: {
> > -               u64 regid;
> > -
> > -               regid = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_INSTR_MASK);
> > -               ret = vgic_v3_cpu_sysregs_uaccess(vcpu, is_write,
> > -                                                 regid, reg);
> > +       case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
> > +               ret = vgic_v3_cpu_sysregs_uaccess(vcpu, attr, is_write);
> 
> Nit: Since @reg that is passed to vgic_v3_attr_regs_access() will be NULL
> for KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS, I think it would be more clear
> if you could update the comment for vgic_v3_attr_regs_access accordingly.
> 
> ----
> /*
>  * vgic_v3_attr_regs_access - allows user space to access VGIC v3 state
>  *
>  * @dev:      kvm device handle
>  * @attr:     kvm device attribute
>  * @reg:      address the value is read or written
>    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>  * @is_write: true if userspace is writing a register
>  */
> static int vgic_v3_attr_regs_access(struct kvm_device *dev,
>                                     struct kvm_device_attr *attr,
>                                     u64 *reg, bool is_write)

@reg disappears completely in patch #12. Do you see value in rewriting
this comment even if I end-up removing it 4 patches down the line?

Thanks,

	M.

-- 
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Re: [PATCH 08/19] KVM: arm64: vgic-v3: Push user access into vgic_v3_cpu_sysregs_uaccess()

[Reiji Watanabe]

Hi Marc,

On Mon, Jul 11, 2022 at 11:53 PM Marc Zyngier <maz@kernel.org> wrote:
>
> Hi Reiji,
>
> On Tue, 12 Jul 2022 07:11:39 +0100,
> Reiji Watanabe <reijiw@google.com> wrote:
> >
> > Hi Marc,
> >
> > On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
> > >
> > > In order to start making the vgic sysreg access from userspace
> > > similar to all the other sysregs, push the userspace memory
> > > access one level down into vgic_v3_cpu_sysregs_uaccess().
> > >
> > > The next step will be to rely on the sysreg infrastructure
> > > to perform this task.
> > >
> > > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > > ---
> > >  arch/arm64/kvm/vgic-sys-reg-v3.c      | 22 +++++++++++++------
> > >  arch/arm64/kvm/vgic/vgic-kvm-device.c | 31 ++++++---------------------
> > >  arch/arm64/kvm/vgic/vgic.h            |  4 ++--
> > >  3 files changed, 23 insertions(+), 34 deletions(-)
> > >
> > > diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
> > > index 85a5e1d15e9f..8c56e285fde9 100644
> > > --- a/arch/arm64/kvm/vgic-sys-reg-v3.c
> > > +++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
> > > @@ -278,15 +278,21 @@ int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *
> > >         return -ENXIO;
> > >  }
> > >
> > > -int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write, u64 id,
> > > -                               u64 *reg)
> > > +int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu,
> > > +                               struct kvm_device_attr *attr,
> > > +                               bool is_write)
> > >  {
> > > +       u64 __user *uaddr = (u64 __user *)(long)attr->addr;
> > >         struct sys_reg_params params;
> > >         const struct sys_reg_desc *r;
> > > -       u64 sysreg = (id & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
> > > +       u64 sysreg;
> > >
> > > -       if (is_write)
> > > -               params.regval = *reg;
> > > +       sysreg = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
> >
> > Why don't you use attr_to_id() here ?
>
> This actually happens in the following patch. Happy to move the change
> here though.

IMHO it makes more sense to have the change in this patch
because vgic_v3_cpu_sysregs_uaccess in this patch already
takes "attr" as the arguments.
Having said that, I'm fine with keeping the current code:)

> >
> >
> > > +
> > > +       if (is_write) {
> > > +               if (get_user(params.regval, uaddr))
> > > +                       return -EFAULT;
> > > +       }
> > >         params.is_write = is_write;
> > >
> > >         r = find_reg_by_id(sysreg, &params, gic_v3_icc_reg_descs,
> > > @@ -297,8 +303,10 @@ int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write, u64 id,
> > >         if (!r->access(vcpu, &params, r))
> > >                 return -EINVAL;
> > >
> > > -       if (!is_write)
> > > -               *reg = params.regval;
> > > +       if (!is_write) {
> > > +               if (put_user(params.regval, uaddr))
> > > +                       return -EFAULT;
> > > +       }
> > >
> > >         return 0;
> > >  }
> > > diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > > index c6d52a1fd9c8..d8269300632d 100644
> > > --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > > +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > > @@ -561,14 +561,9 @@ static int vgic_v3_attr_regs_access(struct kvm_device *dev,
> > >                 if (!is_write)
> > >                         *reg = tmp32;
> > >                 break;
> > > -       case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS: {
> > > -               u64 regid;
> > > -
> > > -               regid = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_INSTR_MASK);
> > > -               ret = vgic_v3_cpu_sysregs_uaccess(vcpu, is_write,
> > > -                                                 regid, reg);
> > > +       case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
> > > +               ret = vgic_v3_cpu_sysregs_uaccess(vcpu, attr, is_write);
> >
> > Nit: Since @reg that is passed to vgic_v3_attr_regs_access() will be NULL
> > for KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS, I think it would be more clear
> > if you could update the comment for vgic_v3_attr_regs_access accordingly.
> >
> > ----
> > /*
> >  * vgic_v3_attr_regs_access - allows user space to access VGIC v3 state
> >  *
> >  * @dev:      kvm device handle
> >  * @attr:     kvm device attribute
> >  * @reg:      address the value is read or written
> >    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >  * @is_write: true if userspace is writing a register
> >  */
> > static int vgic_v3_attr_regs_access(struct kvm_device *dev,
> >                                     struct kvm_device_attr *attr,
> >                                     u64 *reg, bool is_write)
>
> @reg disappears completely in patch #12. Do you see value in rewriting
> this comment even if I end-up removing it 4 patches down the line?

Oh, I haven't seen PATCH#12 yet. Then let me withdraw my comment.

Thank you,
Reiji

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH 09/19] KVM: arm64: vgic-v3: Make the userspace accessors use sysreg API

[Marc Zyngier]

The vgic-v3 sysreg accessors have been ignored as the rest of the
sysreg internal API was avolving, and are stuck with the .access
method (which is normally reserved to the guest's own access)
for the userspace accesses (which should use the .set/.get_user()
methods).

Catch up with the program and repaint all the accessors so that
they fit into the normal userspace model, and plug the result into
the helpers that have been introduced earlier.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic-sys-reg-v3.c | 453 ++++++++++++++++++-------------
 1 file changed, 257 insertions(+), 196 deletions(-)

diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
index 8c56e285fde9..2ca172cdc5c4 100644
--- a/arch/arm64/kvm/vgic-sys-reg-v3.c
+++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
@@ -10,254 +10,331 @@
 #include "vgic/vgic.h"
 #include "sys_regs.h"
 
-static bool access_gic_ctlr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
-			    const struct sys_reg_desc *r)
+static int set_gic_ctlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 val)
 {
 	u32 host_pri_bits, host_id_bits, host_seis, host_a3v, seis, a3v;
 	struct vgic_cpu *vgic_v3_cpu = &vcpu->arch.vgic_cpu;
 	struct vgic_vmcr vmcr;
+
+	vgic_get_vmcr(vcpu, &vmcr);
+
+	/*
+	 * Disallow restoring VM state if not supported by this
+	 * hardware.
+	 */
+	host_pri_bits = ((val & ICC_CTLR_EL1_PRI_BITS_MASK) >>
+			 ICC_CTLR_EL1_PRI_BITS_SHIFT) + 1;
+	if (host_pri_bits > vgic_v3_cpu->num_pri_bits)
+		return -EINVAL;
+
+	vgic_v3_cpu->num_pri_bits = host_pri_bits;
+
+	host_id_bits = (val & ICC_CTLR_EL1_ID_BITS_MASK) >>
+		ICC_CTLR_EL1_ID_BITS_SHIFT;
+	if (host_id_bits > vgic_v3_cpu->num_id_bits)
+		return -EINVAL;
+
+	vgic_v3_cpu->num_id_bits = host_id_bits;
+
+	host_seis = ((kvm_vgic_global_state.ich_vtr_el2 &
+		      ICH_VTR_SEIS_MASK) >> ICH_VTR_SEIS_SHIFT);
+	seis = (val & ICC_CTLR_EL1_SEIS_MASK) >>
+		ICC_CTLR_EL1_SEIS_SHIFT;
+	if (host_seis != seis)
+		return -EINVAL;
+
+	host_a3v = ((kvm_vgic_global_state.ich_vtr_el2 &
+		     ICH_VTR_A3V_MASK) >> ICH_VTR_A3V_SHIFT);
+	a3v = (val & ICC_CTLR_EL1_A3V_MASK) >> ICC_CTLR_EL1_A3V_SHIFT;
+	if (host_a3v != a3v)
+		return -EINVAL;
+
+	/*
+	 * Here set VMCR.CTLR in ICC_CTLR_EL1 layout.
+	 * The vgic_set_vmcr() will convert to ICH_VMCR layout.
+	 */
+	vmcr.cbpr = (val & ICC_CTLR_EL1_CBPR_MASK) >> ICC_CTLR_EL1_CBPR_SHIFT;
+	vmcr.eoim = (val & ICC_CTLR_EL1_EOImode_MASK) >> ICC_CTLR_EL1_EOImode_SHIFT;
+	vgic_set_vmcr(vcpu, &vmcr);
+
+	return 0;
+}
+
+static int get_gic_ctlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 *valp)
+{
+	struct vgic_cpu *vgic_v3_cpu = &vcpu->arch.vgic_cpu;
+	struct vgic_vmcr vmcr;
 	u64 val;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	if (p->is_write) {
-		val = p->regval;
-
-		/*
-		 * Disallow restoring VM state if not supported by this
-		 * hardware.
-		 */
-		host_pri_bits = ((val & ICC_CTLR_EL1_PRI_BITS_MASK) >>
-				 ICC_CTLR_EL1_PRI_BITS_SHIFT) + 1;
-		if (host_pri_bits > vgic_v3_cpu->num_pri_bits)
-			return false;
-
-		vgic_v3_cpu->num_pri_bits = host_pri_bits;
-
-		host_id_bits = (val & ICC_CTLR_EL1_ID_BITS_MASK) >>
-				ICC_CTLR_EL1_ID_BITS_SHIFT;
-		if (host_id_bits > vgic_v3_cpu->num_id_bits)
-			return false;
-
-		vgic_v3_cpu->num_id_bits = host_id_bits;
-
-		host_seis = ((kvm_vgic_global_state.ich_vtr_el2 &
-			     ICH_VTR_SEIS_MASK) >> ICH_VTR_SEIS_SHIFT);
-		seis = (val & ICC_CTLR_EL1_SEIS_MASK) >>
-			ICC_CTLR_EL1_SEIS_SHIFT;
-		if (host_seis != seis)
-			return false;
-
-		host_a3v = ((kvm_vgic_global_state.ich_vtr_el2 &
-			    ICH_VTR_A3V_MASK) >> ICH_VTR_A3V_SHIFT);
-		a3v = (val & ICC_CTLR_EL1_A3V_MASK) >> ICC_CTLR_EL1_A3V_SHIFT;
-		if (host_a3v != a3v)
-			return false;
-
-		/*
-		 * Here set VMCR.CTLR in ICC_CTLR_EL1 layout.
-		 * The vgic_set_vmcr() will convert to ICH_VMCR layout.
-		 */
-		vmcr.cbpr = (val & ICC_CTLR_EL1_CBPR_MASK) >> ICC_CTLR_EL1_CBPR_SHIFT;
-		vmcr.eoim = (val & ICC_CTLR_EL1_EOImode_MASK) >> ICC_CTLR_EL1_EOImode_SHIFT;
-		vgic_set_vmcr(vcpu, &vmcr);
-	} else {
-		val = 0;
-		val |= (vgic_v3_cpu->num_pri_bits - 1) <<
-			ICC_CTLR_EL1_PRI_BITS_SHIFT;
-		val |= vgic_v3_cpu->num_id_bits << ICC_CTLR_EL1_ID_BITS_SHIFT;
-		val |= ((kvm_vgic_global_state.ich_vtr_el2 &
-			ICH_VTR_SEIS_MASK) >> ICH_VTR_SEIS_SHIFT) <<
-			ICC_CTLR_EL1_SEIS_SHIFT;
-		val |= ((kvm_vgic_global_state.ich_vtr_el2 &
-			ICH_VTR_A3V_MASK) >> ICH_VTR_A3V_SHIFT) <<
-			ICC_CTLR_EL1_A3V_SHIFT;
-		/*
-		 * The VMCR.CTLR value is in ICC_CTLR_EL1 layout.
-		 * Extract it directly using ICC_CTLR_EL1 reg definitions.
-		 */
-		val |= (vmcr.cbpr << ICC_CTLR_EL1_CBPR_SHIFT) & ICC_CTLR_EL1_CBPR_MASK;
-		val |= (vmcr.eoim << ICC_CTLR_EL1_EOImode_SHIFT) & ICC_CTLR_EL1_EOImode_MASK;
-
-		p->regval = val;
-	}
+	val = 0;
+	val |= (vgic_v3_cpu->num_pri_bits - 1) << ICC_CTLR_EL1_PRI_BITS_SHIFT;
+	val |= vgic_v3_cpu->num_id_bits << ICC_CTLR_EL1_ID_BITS_SHIFT;
+	val |= ((kvm_vgic_global_state.ich_vtr_el2 &
+		 ICH_VTR_SEIS_MASK) >> ICH_VTR_SEIS_SHIFT) <<
+		ICC_CTLR_EL1_SEIS_SHIFT;
+	val |= ((kvm_vgic_global_state.ich_vtr_el2 &
+		 ICH_VTR_A3V_MASK) >> ICH_VTR_A3V_SHIFT) <<
+		ICC_CTLR_EL1_A3V_SHIFT;
+	/*
+	 * The VMCR.CTLR value is in ICC_CTLR_EL1 layout.
+	 * Extract it directly using ICC_CTLR_EL1 reg definitions.
+	 */
+	val |= (vmcr.cbpr << ICC_CTLR_EL1_CBPR_SHIFT) & ICC_CTLR_EL1_CBPR_MASK;
+	val |= (vmcr.eoim << ICC_CTLR_EL1_EOImode_SHIFT) & ICC_CTLR_EL1_EOImode_MASK;
+
+	*valp = val;
 
-	return true;
+	return 0;
 }
 
-static bool access_gic_pmr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
-			   const struct sys_reg_desc *r)
+static int set_gic_pmr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+		       u64 val)
 {
 	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	if (p->is_write) {
-		vmcr.pmr = (p->regval & ICC_PMR_EL1_MASK) >> ICC_PMR_EL1_SHIFT;
-		vgic_set_vmcr(vcpu, &vmcr);
-	} else {
-		p->regval = (vmcr.pmr << ICC_PMR_EL1_SHIFT) & ICC_PMR_EL1_MASK;
-	}
+	vmcr.pmr = (val & ICC_PMR_EL1_MASK) >> ICC_PMR_EL1_SHIFT;
+	vgic_set_vmcr(vcpu, &vmcr);
 
-	return true;
+	return 0;
 }
 
-static bool access_gic_bpr0(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
-			    const struct sys_reg_desc *r)
+static int get_gic_pmr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+		       u64 *val)
 {
 	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	if (p->is_write) {
-		vmcr.bpr = (p->regval & ICC_BPR0_EL1_MASK) >>
-			    ICC_BPR0_EL1_SHIFT;
-		vgic_set_vmcr(vcpu, &vmcr);
-	} else {
-		p->regval = (vmcr.bpr << ICC_BPR0_EL1_SHIFT) &
-			     ICC_BPR0_EL1_MASK;
-	}
+	*val = (vmcr.pmr << ICC_PMR_EL1_SHIFT) & ICC_PMR_EL1_MASK;
 
-	return true;
+	return 0;
 }
 
-static bool access_gic_bpr1(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
-			    const struct sys_reg_desc *r)
+static int set_gic_bpr0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 val)
 {
 	struct vgic_vmcr vmcr;
 
-	if (!p->is_write)
-		p->regval = 0;
+	vgic_get_vmcr(vcpu, &vmcr);
+	vmcr.bpr = (val & ICC_BPR0_EL1_MASK) >> ICC_BPR0_EL1_SHIFT;
+	vgic_set_vmcr(vcpu, &vmcr);
+
+	return 0;
+}
+
+static int get_gic_bpr0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 *val)
+{
+	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	if (!vmcr.cbpr) {
-		if (p->is_write) {
-			vmcr.abpr = (p->regval & ICC_BPR1_EL1_MASK) >>
-				     ICC_BPR1_EL1_SHIFT;
-			vgic_set_vmcr(vcpu, &vmcr);
-		} else {
-			p->regval = (vmcr.abpr << ICC_BPR1_EL1_SHIFT) &
-				     ICC_BPR1_EL1_MASK;
-		}
-	} else {
-		if (!p->is_write)
-			p->regval = min((vmcr.bpr + 1), 7U);
-	}
+	*val = (vmcr.bpr << ICC_BPR0_EL1_SHIFT) & ICC_BPR0_EL1_MASK;
 
-	return true;
+	return 0;
 }
 
-static bool access_gic_grpen0(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
-			      const struct sys_reg_desc *r)
+static int set_gic_bpr1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 val)
 {
 	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	if (p->is_write) {
-		vmcr.grpen0 = (p->regval & ICC_IGRPEN0_EL1_MASK) >>
-			       ICC_IGRPEN0_EL1_SHIFT;
+	if (!vmcr.cbpr) {
+		vmcr.abpr = (val & ICC_BPR1_EL1_MASK) >> ICC_BPR1_EL1_SHIFT;
 		vgic_set_vmcr(vcpu, &vmcr);
-	} else {
-		p->regval = (vmcr.grpen0 << ICC_IGRPEN0_EL1_SHIFT) &
-			     ICC_IGRPEN0_EL1_MASK;
 	}
 
-	return true;
+	return 0;
 }
 
-static bool access_gic_grpen1(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
-			      const struct sys_reg_desc *r)
+static int get_gic_bpr1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 *val)
 {
 	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	if (p->is_write) {
-		vmcr.grpen1 = (p->regval & ICC_IGRPEN1_EL1_MASK) >>
-			       ICC_IGRPEN1_EL1_SHIFT;
-		vgic_set_vmcr(vcpu, &vmcr);
-	} else {
-		p->regval = (vmcr.grpen1 << ICC_IGRPEN1_EL1_SHIFT) &
-			     ICC_IGRPEN1_EL1_MASK;
-	}
+	if (!vmcr.cbpr)
+		*val = (vmcr.abpr << ICC_BPR1_EL1_SHIFT) & ICC_BPR1_EL1_MASK;
+	else
+		*val = min((vmcr.bpr + 1), 7U);
+
+
+	return 0;
+}
+
+static int set_gic_grpen0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			  u64 val)
+{
+	struct vgic_vmcr vmcr;
+
+	vgic_get_vmcr(vcpu, &vmcr);
+	vmcr.grpen0 = (val & ICC_IGRPEN0_EL1_MASK) >> ICC_IGRPEN0_EL1_SHIFT;
+	vgic_set_vmcr(vcpu, &vmcr);
+
+	return 0;
+}
+
+static int get_gic_grpen0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			  u64 *val)
+{
+	struct vgic_vmcr vmcr;
+
+	vgic_get_vmcr(vcpu, &vmcr);
+	*val = (vmcr.grpen0 << ICC_IGRPEN0_EL1_SHIFT) & ICC_IGRPEN0_EL1_MASK;
 
-	return true;
+	return 0;
 }
 
-static void vgic_v3_access_apr_reg(struct kvm_vcpu *vcpu,
-				   struct sys_reg_params *p, u8 apr, u8 idx)
+static int set_gic_grpen1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			  u64 val)
+{
+	struct vgic_vmcr vmcr;
+
+	vgic_get_vmcr(vcpu, &vmcr);
+	vmcr.grpen1 = (val & ICC_IGRPEN1_EL1_MASK) >> ICC_IGRPEN1_EL1_SHIFT;
+	vgic_set_vmcr(vcpu, &vmcr);
+
+	return 0;
+}
+
+static int get_gic_grpen1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			  u64 *val)
+{
+	struct vgic_vmcr vmcr;
+
+	vgic_get_vmcr(vcpu, &vmcr);
+	*val = (vmcr.grpen1 << ICC_IGRPEN1_EL1_SHIFT) & ICC_IGRPEN1_EL1_MASK;
+
+	return 0;
+}
+
+static void set_apr_reg(struct kvm_vcpu *vcpu, u64 val, u8 apr, u8 idx)
 {
 	struct vgic_v3_cpu_if *vgicv3 = &vcpu->arch.vgic_cpu.vgic_v3;
-	uint32_t *ap_reg;
 
 	if (apr)
-		ap_reg = &vgicv3->vgic_ap1r[idx];
+		vgicv3->vgic_ap1r[idx] = val;
 	else
-		ap_reg = &vgicv3->vgic_ap0r[idx];
+		vgicv3->vgic_ap0r[idx] = val;
+}
+
+static u64 get_apr_reg(struct kvm_vcpu *vcpu, u8 apr, u8 idx)
+{
+	struct vgic_v3_cpu_if *vgicv3 = &vcpu->arch.vgic_cpu.vgic_v3;
 
-	if (p->is_write)
-		*ap_reg = p->regval;
+	if (apr)
+		return vgicv3->vgic_ap1r[idx];
 	else
-		p->regval = *ap_reg;
+		return vgicv3->vgic_ap0r[idx];
+}
+
+static int set_gic_ap0r(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 val)
+
+{
+	u8 idx = r->Op2 & 3;
+
+	if (idx > vgic_v3_max_apr_idx(vcpu))
+		return -EINVAL;
+
+	set_apr_reg(vcpu, val, 0, idx);
+	return 0;
 }
 
-static bool access_gic_aprn(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
-			    const struct sys_reg_desc *r, u8 apr)
+static int get_gic_ap0r(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 *val)
 {
 	u8 idx = r->Op2 & 3;
 
 	if (idx > vgic_v3_max_apr_idx(vcpu))
-		goto err;
+		return -EINVAL;
 
-	vgic_v3_access_apr_reg(vcpu, p, apr, idx);
-	return true;
-err:
-	if (!p->is_write)
-		p->regval = 0;
+	*val = get_apr_reg(vcpu, 0, idx);
 
-	return false;
+	return 0;
 }
 
-static bool access_gic_ap0r(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
-			    const struct sys_reg_desc *r)
+static int set_gic_ap1r(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 val)
+
+{
+	u8 idx = r->Op2 & 3;
+
+	if (idx > vgic_v3_max_apr_idx(vcpu))
+		return -EINVAL;
+
+	set_apr_reg(vcpu, val, 1, idx);
+	return 0;
+}
 
+static int get_gic_ap1r(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 *val)
 {
-	return access_gic_aprn(vcpu, p, r, 0);
+	u8 idx = r->Op2 & 3;
+
+	if (idx > vgic_v3_max_apr_idx(vcpu))
+		return -EINVAL;
+
+	*val = get_apr_reg(vcpu, 1, idx);
+
+	return 0;
 }
 
-static bool access_gic_ap1r(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
-			    const struct sys_reg_desc *r)
+static int set_gic_sre(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+		       u64 val)
 {
-	return access_gic_aprn(vcpu, p, r, 1);
+	/* Validate SRE bit */
+	if (!(val & ICC_SRE_EL1_SRE))
+		return -EINVAL;
+
+	return 0;
 }
 
-static bool access_gic_sre(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
-			   const struct sys_reg_desc *r)
+static int get_gic_sre(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+		       u64 *val)
 {
 	struct vgic_v3_cpu_if *vgicv3 = &vcpu->arch.vgic_cpu.vgic_v3;
 
 	/* Validate SRE bit */
-	if (p->is_write) {
-		if (!(p->regval & ICC_SRE_EL1_SRE))
-			return false;
-	} else {
-		p->regval = vgicv3->vgic_sre;
-	}
+	*val = vgicv3->vgic_sre;
 
-	return true;
+	return 0;
 }
+
 static const struct sys_reg_desc gic_v3_icc_reg_descs[] = {
-	{ SYS_DESC(SYS_ICC_PMR_EL1), access_gic_pmr },
-	{ SYS_DESC(SYS_ICC_BPR0_EL1), access_gic_bpr0 },
-	{ SYS_DESC(SYS_ICC_AP0R0_EL1), access_gic_ap0r },
-	{ SYS_DESC(SYS_ICC_AP0R1_EL1), access_gic_ap0r },
-	{ SYS_DESC(SYS_ICC_AP0R2_EL1), access_gic_ap0r },
-	{ SYS_DESC(SYS_ICC_AP0R3_EL1), access_gic_ap0r },
-	{ SYS_DESC(SYS_ICC_AP1R0_EL1), access_gic_ap1r },
-	{ SYS_DESC(SYS_ICC_AP1R1_EL1), access_gic_ap1r },
-	{ SYS_DESC(SYS_ICC_AP1R2_EL1), access_gic_ap1r },
-	{ SYS_DESC(SYS_ICC_AP1R3_EL1), access_gic_ap1r },
-	{ SYS_DESC(SYS_ICC_BPR1_EL1), access_gic_bpr1 },
-	{ SYS_DESC(SYS_ICC_CTLR_EL1), access_gic_ctlr },
-	{ SYS_DESC(SYS_ICC_SRE_EL1), access_gic_sre },
-	{ SYS_DESC(SYS_ICC_IGRPEN0_EL1), access_gic_grpen0 },
-	{ SYS_DESC(SYS_ICC_IGRPEN1_EL1), access_gic_grpen1 },
+	{ SYS_DESC(SYS_ICC_PMR_EL1),
+	  .set_user = set_gic_pmr, .get_user = get_gic_pmr, },
+	{ SYS_DESC(SYS_ICC_BPR0_EL1),
+	  .set_user = set_gic_bpr0, .get_user = get_gic_bpr0, },
+	{ SYS_DESC(SYS_ICC_AP0R0_EL1),
+	  .set_user = set_gic_ap0r, .get_user = get_gic_ap0r, },
+	{ SYS_DESC(SYS_ICC_AP0R1_EL1),
+	  .set_user = set_gic_ap0r, .get_user = get_gic_ap0r, },
+	{ SYS_DESC(SYS_ICC_AP0R2_EL1),
+	  .set_user = set_gic_ap0r, .get_user = get_gic_ap0r, },
+	{ SYS_DESC(SYS_ICC_AP0R3_EL1),
+	  .set_user = set_gic_ap0r, .get_user = get_gic_ap0r, },
+	{ SYS_DESC(SYS_ICC_AP1R0_EL1),
+	  .set_user = set_gic_ap1r, .get_user = get_gic_ap1r, },
+	{ SYS_DESC(SYS_ICC_AP1R1_EL1),
+	  .set_user = set_gic_ap1r, .get_user = get_gic_ap1r, },
+	{ SYS_DESC(SYS_ICC_AP1R2_EL1),
+	  .set_user = set_gic_ap1r, .get_user = get_gic_ap1r, },
+	{ SYS_DESC(SYS_ICC_AP1R3_EL1),
+	  .set_user = set_gic_ap1r, .get_user = get_gic_ap1r, },
+	{ SYS_DESC(SYS_ICC_BPR1_EL1),
+	  .set_user = set_gic_bpr1, .get_user = get_gic_bpr1, },
+	{ SYS_DESC(SYS_ICC_CTLR_EL1),
+	  .set_user = set_gic_ctlr, .get_user = get_gic_ctlr, },
+	{ SYS_DESC(SYS_ICC_SRE_EL1),
+	  .set_user = set_gic_sre, .get_user = get_gic_sre, },
+	{ SYS_DESC(SYS_ICC_IGRPEN0_EL1),
+	  .set_user = set_gic_grpen0, .get_user = get_gic_grpen0, },
+	{ SYS_DESC(SYS_ICC_IGRPEN1_EL1),
+	  .set_user = set_gic_grpen1, .get_user = get_gic_grpen1, },
 };
 
 static u64 attr_to_id(u64 attr)
@@ -282,31 +359,15 @@ int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu,
 				struct kvm_device_attr *attr,
 				bool is_write)
 {
-	u64 __user *uaddr = (u64 __user *)(long)attr->addr;
-	struct sys_reg_params params;
-	const struct sys_reg_desc *r;
-	u64 sysreg;
-
-	sysreg = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
-
-	if (is_write) {
-		if (get_user(params.regval, uaddr))
-			return -EFAULT;
-	}
-	params.is_write = is_write;
-
-	r = find_reg_by_id(sysreg, &params, gic_v3_icc_reg_descs,
-			   ARRAY_SIZE(gic_v3_icc_reg_descs));
-	if (!r)
-		return -ENXIO;
-
-	if (!r->access(vcpu, &params, r))
-		return -EINVAL;
-
-	if (!is_write) {
-		if (put_user(params.regval, uaddr))
-			return -EFAULT;
-	}
-
-	return 0;
+	struct kvm_one_reg reg = {
+		.id	= attr_to_id(attr->attr),
+		.addr	= attr->addr,
+	};
+
+	if (is_write)
+		return kvm_sys_reg_set_user(vcpu, &reg, gic_v3_icc_reg_descs,
+					    ARRAY_SIZE(gic_v3_icc_reg_descs));
+	else
+		return kvm_sys_reg_get_user(vcpu, &reg, gic_v3_icc_reg_descs,
+					    ARRAY_SIZE(gic_v3_icc_reg_descs));
 }
-- 
2.34.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH 09/19] KVM: arm64: vgic-v3: Make the userspace accessors use sysreg API

[Reiji Watanabe]

Hi Marc,

On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
>
> The vgic-v3 sysreg accessors have been ignored as the rest of the
> sysreg internal API was avolving, and are stuck with the .access

Nit: s/avolving/evolving/ ?


> method (which is normally reserved to the guest's own access)
> for the userspace accesses (which should use the .set/.get_user()
> methods).
>
> Catch up with the program and repaint all the accessors so that
> they fit into the normal userspace model, and plug the result into
> the helpers that have been introduced earlier.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/vgic-sys-reg-v3.c | 453 ++++++++++++++++++-------------
>  1 file changed, 257 insertions(+), 196 deletions(-)
>
> diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
> index 8c56e285fde9..2ca172cdc5c4 100644
> --- a/arch/arm64/kvm/vgic-sys-reg-v3.c
> +++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
> @@ -10,254 +10,331 @@
>  #include "vgic/vgic.h"
>  #include "sys_regs.h"
>
> -static bool access_gic_ctlr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> -                           const struct sys_reg_desc *r)
> +static int set_gic_ctlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                       u64 val)
>  {
>         u32 host_pri_bits, host_id_bits, host_seis, host_a3v, seis, a3v;
>         struct vgic_cpu *vgic_v3_cpu = &vcpu->arch.vgic_cpu;
>         struct vgic_vmcr vmcr;
> +
> +       vgic_get_vmcr(vcpu, &vmcr);
> +
> +       /*
> +        * Disallow restoring VM state if not supported by this
> +        * hardware.
> +        */
> +       host_pri_bits = ((val & ICC_CTLR_EL1_PRI_BITS_MASK) >>
> +                        ICC_CTLR_EL1_PRI_BITS_SHIFT) + 1;
> +       if (host_pri_bits > vgic_v3_cpu->num_pri_bits)
> +               return -EINVAL;
> +
> +       vgic_v3_cpu->num_pri_bits = host_pri_bits;
> +
> +       host_id_bits = (val & ICC_CTLR_EL1_ID_BITS_MASK) >>
> +               ICC_CTLR_EL1_ID_BITS_SHIFT;
> +       if (host_id_bits > vgic_v3_cpu->num_id_bits)
> +               return -EINVAL;
> +
> +       vgic_v3_cpu->num_id_bits = host_id_bits;
> +
> +       host_seis = ((kvm_vgic_global_state.ich_vtr_el2 &
> +                     ICH_VTR_SEIS_MASK) >> ICH_VTR_SEIS_SHIFT);
> +       seis = (val & ICC_CTLR_EL1_SEIS_MASK) >>
> +               ICC_CTLR_EL1_SEIS_SHIFT;
> +       if (host_seis != seis)
> +               return -EINVAL;
> +
> +       host_a3v = ((kvm_vgic_global_state.ich_vtr_el2 &
> +                    ICH_VTR_A3V_MASK) >> ICH_VTR_A3V_SHIFT);
> +       a3v = (val & ICC_CTLR_EL1_A3V_MASK) >> ICC_CTLR_EL1_A3V_SHIFT;
> +       if (host_a3v != a3v)
> +               return -EINVAL;
> +
> +       /*
> +        * Here set VMCR.CTLR in ICC_CTLR_EL1 layout.
> +        * The vgic_set_vmcr() will convert to ICH_VMCR layout.
> +        */
> +       vmcr.cbpr = (val & ICC_CTLR_EL1_CBPR_MASK) >> ICC_CTLR_EL1_CBPR_SHIFT;
> +       vmcr.eoim = (val & ICC_CTLR_EL1_EOImode_MASK) >> ICC_CTLR_EL1_EOImode_SHIFT;
> +       vgic_set_vmcr(vcpu, &vmcr);
> +
> +       return 0;
> +}
> +
> +static int get_gic_ctlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                       u64 *valp)
> +{
> +       struct vgic_cpu *vgic_v3_cpu = &vcpu->arch.vgic_cpu;
> +       struct vgic_vmcr vmcr;
>         u64 val;
>
>         vgic_get_vmcr(vcpu, &vmcr);
> -       if (p->is_write) {
> -               val = p->regval;
> -
> -               /*
> -                * Disallow restoring VM state if not supported by this
> -                * hardware.
> -                */
> -               host_pri_bits = ((val & ICC_CTLR_EL1_PRI_BITS_MASK) >>
> -                                ICC_CTLR_EL1_PRI_BITS_SHIFT) + 1;
> -               if (host_pri_bits > vgic_v3_cpu->num_pri_bits)
> -                       return false;
> -
> -               vgic_v3_cpu->num_pri_bits = host_pri_bits;
> -
> -               host_id_bits = (val & ICC_CTLR_EL1_ID_BITS_MASK) >>
> -                               ICC_CTLR_EL1_ID_BITS_SHIFT;
> -               if (host_id_bits > vgic_v3_cpu->num_id_bits)
> -                       return false;
> -
> -               vgic_v3_cpu->num_id_bits = host_id_bits;
> -
> -               host_seis = ((kvm_vgic_global_state.ich_vtr_el2 &
> -                            ICH_VTR_SEIS_MASK) >> ICH_VTR_SEIS_SHIFT);
> -               seis = (val & ICC_CTLR_EL1_SEIS_MASK) >>
> -                       ICC_CTLR_EL1_SEIS_SHIFT;
> -               if (host_seis != seis)
> -                       return false;
> -
> -               host_a3v = ((kvm_vgic_global_state.ich_vtr_el2 &
> -                           ICH_VTR_A3V_MASK) >> ICH_VTR_A3V_SHIFT);
> -               a3v = (val & ICC_CTLR_EL1_A3V_MASK) >> ICC_CTLR_EL1_A3V_SHIFT;
> -               if (host_a3v != a3v)
> -                       return false;
> -
> -               /*
> -                * Here set VMCR.CTLR in ICC_CTLR_EL1 layout.
> -                * The vgic_set_vmcr() will convert to ICH_VMCR layout.
> -                */
> -               vmcr.cbpr = (val & ICC_CTLR_EL1_CBPR_MASK) >> ICC_CTLR_EL1_CBPR_SHIFT;
> -               vmcr.eoim = (val & ICC_CTLR_EL1_EOImode_MASK) >> ICC_CTLR_EL1_EOImode_SHIFT;
> -               vgic_set_vmcr(vcpu, &vmcr);
> -       } else {
> -               val = 0;
> -               val |= (vgic_v3_cpu->num_pri_bits - 1) <<
> -                       ICC_CTLR_EL1_PRI_BITS_SHIFT;
> -               val |= vgic_v3_cpu->num_id_bits << ICC_CTLR_EL1_ID_BITS_SHIFT;
> -               val |= ((kvm_vgic_global_state.ich_vtr_el2 &
> -                       ICH_VTR_SEIS_MASK) >> ICH_VTR_SEIS_SHIFT) <<
> -                       ICC_CTLR_EL1_SEIS_SHIFT;
> -               val |= ((kvm_vgic_global_state.ich_vtr_el2 &
> -                       ICH_VTR_A3V_MASK) >> ICH_VTR_A3V_SHIFT) <<
> -                       ICC_CTLR_EL1_A3V_SHIFT;
> -               /*
> -                * The VMCR.CTLR value is in ICC_CTLR_EL1 layout.
> -                * Extract it directly using ICC_CTLR_EL1 reg definitions.
> -                */
> -               val |= (vmcr.cbpr << ICC_CTLR_EL1_CBPR_SHIFT) & ICC_CTLR_EL1_CBPR_MASK;
> -               val |= (vmcr.eoim << ICC_CTLR_EL1_EOImode_SHIFT) & ICC_CTLR_EL1_EOImode_MASK;
> -
> -               p->regval = val;
> -       }
> +       val = 0;
> +       val |= (vgic_v3_cpu->num_pri_bits - 1) << ICC_CTLR_EL1_PRI_BITS_SHIFT;
> +       val |= vgic_v3_cpu->num_id_bits << ICC_CTLR_EL1_ID_BITS_SHIFT;
> +       val |= ((kvm_vgic_global_state.ich_vtr_el2 &
> +                ICH_VTR_SEIS_MASK) >> ICH_VTR_SEIS_SHIFT) <<
> +               ICC_CTLR_EL1_SEIS_SHIFT;
> +       val |= ((kvm_vgic_global_state.ich_vtr_el2 &
> +                ICH_VTR_A3V_MASK) >> ICH_VTR_A3V_SHIFT) <<
> +               ICC_CTLR_EL1_A3V_SHIFT;
> +       /*
> +        * The VMCR.CTLR value is in ICC_CTLR_EL1 layout.
> +        * Extract it directly using ICC_CTLR_EL1 reg definitions.
> +        */
> +       val |= (vmcr.cbpr << ICC_CTLR_EL1_CBPR_SHIFT) & ICC_CTLR_EL1_CBPR_MASK;
> +       val |= (vmcr.eoim << ICC_CTLR_EL1_EOImode_SHIFT) & ICC_CTLR_EL1_EOImode_MASK;
> +
> +       *valp = val;
>
> -       return true;
> +       return 0;
>  }
>
> -static bool access_gic_pmr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> -                          const struct sys_reg_desc *r)
> +static int set_gic_pmr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                      u64 val)
>  {
>         struct vgic_vmcr vmcr;
>
>         vgic_get_vmcr(vcpu, &vmcr);
> -       if (p->is_write) {
> -               vmcr.pmr = (p->regval & ICC_PMR_EL1_MASK) >> ICC_PMR_EL1_SHIFT;
> -               vgic_set_vmcr(vcpu, &vmcr);
> -       } else {
> -               p->regval = (vmcr.pmr << ICC_PMR_EL1_SHIFT) & ICC_PMR_EL1_MASK;
> -       }
> +       vmcr.pmr = (val & ICC_PMR_EL1_MASK) >> ICC_PMR_EL1_SHIFT;
> +       vgic_set_vmcr(vcpu, &vmcr);
>
> -       return true;
> +       return 0;
>  }
>
> -static bool access_gic_bpr0(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> -                           const struct sys_reg_desc *r)
> +static int get_gic_pmr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                      u64 *val)
>  {
>         struct vgic_vmcr vmcr;
>
>         vgic_get_vmcr(vcpu, &vmcr);
> -       if (p->is_write) {
> -               vmcr.bpr = (p->regval & ICC_BPR0_EL1_MASK) >>
> -                           ICC_BPR0_EL1_SHIFT;
> -               vgic_set_vmcr(vcpu, &vmcr);
> -       } else {
> -               p->regval = (vmcr.bpr << ICC_BPR0_EL1_SHIFT) &
> -                            ICC_BPR0_EL1_MASK;
> -       }
> +       *val = (vmcr.pmr << ICC_PMR_EL1_SHIFT) & ICC_PMR_EL1_MASK;
>
> -       return true;
> +       return 0;
>  }
>
> -static bool access_gic_bpr1(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> -                           const struct sys_reg_desc *r)
> +static int set_gic_bpr0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                       u64 val)
>  {
>         struct vgic_vmcr vmcr;
>
> -       if (!p->is_write)
> -               p->regval = 0;
> +       vgic_get_vmcr(vcpu, &vmcr);
> +       vmcr.bpr = (val & ICC_BPR0_EL1_MASK) >> ICC_BPR0_EL1_SHIFT;
> +       vgic_set_vmcr(vcpu, &vmcr);
> +
> +       return 0;
> +}
> +
> +static int get_gic_bpr0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                       u64 *val)
> +{
> +       struct vgic_vmcr vmcr;
>
>         vgic_get_vmcr(vcpu, &vmcr);
> -       if (!vmcr.cbpr) {
> -               if (p->is_write) {
> -                       vmcr.abpr = (p->regval & ICC_BPR1_EL1_MASK) >>
> -                                    ICC_BPR1_EL1_SHIFT;
> -                       vgic_set_vmcr(vcpu, &vmcr);
> -               } else {
> -                       p->regval = (vmcr.abpr << ICC_BPR1_EL1_SHIFT) &
> -                                    ICC_BPR1_EL1_MASK;
> -               }
> -       } else {
> -               if (!p->is_write)
> -                       p->regval = min((vmcr.bpr + 1), 7U);
> -       }
> +       *val = (vmcr.bpr << ICC_BPR0_EL1_SHIFT) & ICC_BPR0_EL1_MASK;
>
> -       return true;
> +       return 0;
>  }
>
> -static bool access_gic_grpen0(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> -                             const struct sys_reg_desc *r)
> +static int set_gic_bpr1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                       u64 val)
>  {
>         struct vgic_vmcr vmcr;
>
>         vgic_get_vmcr(vcpu, &vmcr);
> -       if (p->is_write) {
> -               vmcr.grpen0 = (p->regval & ICC_IGRPEN0_EL1_MASK) >>
> -                              ICC_IGRPEN0_EL1_SHIFT;
> +       if (!vmcr.cbpr) {
> +               vmcr.abpr = (val & ICC_BPR1_EL1_MASK) >> ICC_BPR1_EL1_SHIFT;
>                 vgic_set_vmcr(vcpu, &vmcr);
> -       } else {
> -               p->regval = (vmcr.grpen0 << ICC_IGRPEN0_EL1_SHIFT) &
> -                            ICC_IGRPEN0_EL1_MASK;
>         }
>
> -       return true;
> +       return 0;
>  }
>
> -static bool access_gic_grpen1(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> -                             const struct sys_reg_desc *r)
> +static int get_gic_bpr1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                       u64 *val)
>  {
>         struct vgic_vmcr vmcr;
>
>         vgic_get_vmcr(vcpu, &vmcr);
> -       if (p->is_write) {
> -               vmcr.grpen1 = (p->regval & ICC_IGRPEN1_EL1_MASK) >>
> -                              ICC_IGRPEN1_EL1_SHIFT;
> -               vgic_set_vmcr(vcpu, &vmcr);
> -       } else {
> -               p->regval = (vmcr.grpen1 << ICC_IGRPEN1_EL1_SHIFT) &
> -                            ICC_IGRPEN1_EL1_MASK;
> -       }
> +       if (!vmcr.cbpr)
> +               *val = (vmcr.abpr << ICC_BPR1_EL1_SHIFT) & ICC_BPR1_EL1_MASK;
> +       else
> +               *val = min((vmcr.bpr + 1), 7U);
> +
> +
> +       return 0;
> +}
> +
> +static int set_gic_grpen0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                         u64 val)
> +{
> +       struct vgic_vmcr vmcr;
> +
> +       vgic_get_vmcr(vcpu, &vmcr);
> +       vmcr.grpen0 = (val & ICC_IGRPEN0_EL1_MASK) >> ICC_IGRPEN0_EL1_SHIFT;
> +       vgic_set_vmcr(vcpu, &vmcr);
> +
> +       return 0;
> +}
> +
> +static int get_gic_grpen0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                         u64 *val)
> +{
> +       struct vgic_vmcr vmcr;
> +
> +       vgic_get_vmcr(vcpu, &vmcr);
> +       *val = (vmcr.grpen0 << ICC_IGRPEN0_EL1_SHIFT) & ICC_IGRPEN0_EL1_MASK;
>
> -       return true;
> +       return 0;
>  }
>
> -static void vgic_v3_access_apr_reg(struct kvm_vcpu *vcpu,
> -                                  struct sys_reg_params *p, u8 apr, u8 idx)
> +static int set_gic_grpen1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                         u64 val)
> +{
> +       struct vgic_vmcr vmcr;
> +
> +       vgic_get_vmcr(vcpu, &vmcr);
> +       vmcr.grpen1 = (val & ICC_IGRPEN1_EL1_MASK) >> ICC_IGRPEN1_EL1_SHIFT;
> +       vgic_set_vmcr(vcpu, &vmcr);
> +
> +       return 0;
> +}
> +
> +static int get_gic_grpen1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                         u64 *val)
> +{
> +       struct vgic_vmcr vmcr;
> +
> +       vgic_get_vmcr(vcpu, &vmcr);
> +       *val = (vmcr.grpen1 << ICC_IGRPEN1_EL1_SHIFT) & ICC_IGRPEN1_EL1_MASK;
> +
> +       return 0;
> +}
> +
> +static void set_apr_reg(struct kvm_vcpu *vcpu, u64 val, u8 apr, u8 idx)
>  {
>         struct vgic_v3_cpu_if *vgicv3 = &vcpu->arch.vgic_cpu.vgic_v3;
> -       uint32_t *ap_reg;
>
>         if (apr)
> -               ap_reg = &vgicv3->vgic_ap1r[idx];
> +               vgicv3->vgic_ap1r[idx] = val;
>         else
> -               ap_reg = &vgicv3->vgic_ap0r[idx];
> +               vgicv3->vgic_ap0r[idx] = val;
> +}
> +
> +static u64 get_apr_reg(struct kvm_vcpu *vcpu, u8 apr, u8 idx)
> +{
> +       struct vgic_v3_cpu_if *vgicv3 = &vcpu->arch.vgic_cpu.vgic_v3;
>
> -       if (p->is_write)
> -               *ap_reg = p->regval;
> +       if (apr)
> +               return vgicv3->vgic_ap1r[idx];
>         else
> -               p->regval = *ap_reg;
> +               return vgicv3->vgic_ap0r[idx];
> +}
> +
> +static int set_gic_ap0r(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                       u64 val)
> +
> +{
> +       u8 idx = r->Op2 & 3;
> +
> +       if (idx > vgic_v3_max_apr_idx(vcpu))
> +               return -EINVAL;
> +
> +       set_apr_reg(vcpu, val, 0, idx);
> +       return 0;
>  }
>
> -static bool access_gic_aprn(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> -                           const struct sys_reg_desc *r, u8 apr)
> +static int get_gic_ap0r(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                       u64 *val)
>  {
>         u8 idx = r->Op2 & 3;
>
>         if (idx > vgic_v3_max_apr_idx(vcpu))
> -               goto err;
> +               return -EINVAL;
>
> -       vgic_v3_access_apr_reg(vcpu, p, apr, idx);
> -       return true;
> -err:
> -       if (!p->is_write)
> -               p->regval = 0;
> +       *val = get_apr_reg(vcpu, 0, idx);
>
> -       return false;
> +       return 0;
>  }
>
> -static bool access_gic_ap0r(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> -                           const struct sys_reg_desc *r)
> +static int set_gic_ap1r(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                       u64 val)
> +
> +{
> +       u8 idx = r->Op2 & 3;
> +
> +       if (idx > vgic_v3_max_apr_idx(vcpu))
> +               return -EINVAL;
> +
> +       set_apr_reg(vcpu, val, 1, idx);
> +       return 0;
> +}
>
> +static int get_gic_ap1r(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                       u64 *val)
>  {
> -       return access_gic_aprn(vcpu, p, r, 0);
> +       u8 idx = r->Op2 & 3;
> +
> +       if (idx > vgic_v3_max_apr_idx(vcpu))
> +               return -EINVAL;
> +
> +       *val = get_apr_reg(vcpu, 1, idx);
> +
> +       return 0;
>  }
>
> -static bool access_gic_ap1r(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> -                           const struct sys_reg_desc *r)
> +static int set_gic_sre(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                      u64 val)
>  {
> -       return access_gic_aprn(vcpu, p, r, 1);
> +       /* Validate SRE bit */
> +       if (!(val & ICC_SRE_EL1_SRE))
> +               return -EINVAL;
> +
> +       return 0;
>  }
>
> -static bool access_gic_sre(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> -                          const struct sys_reg_desc *r)
> +static int get_gic_sre(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> +                      u64 *val)
>  {
>         struct vgic_v3_cpu_if *vgicv3 = &vcpu->arch.vgic_cpu.vgic_v3;
>
>         /* Validate SRE bit */

I don't think this comment is needed here because this
function doesn't validate the bit (I believe the comment
was just for the write case).

Otherwise,

Reviewed-by: Reiji Watanabe <reijiw@google.com>

Thank you,
Reiji

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[PATCH 10/19] KVM: arm64: vgic-v3: Convert userspace accessors over to FIELD_GET/FIELD_PREP

[Marc Zyngier]

The GICv3 userspace accessors are all about dealing with conversion
between fields from architectural registers and internal representations.

However, and owing to the age of this code, the accessors use
a combination of shift/mask that is hard to read. It is nonetheless
easy to make it better by using the FIELD_{GET,PREP} macros that solely
rely on a mask.

This results in somewhat nicer looking code, and is probably easier
to maintain.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic-sys-reg-v3.c | 60 ++++++++++++++------------------
 1 file changed, 27 insertions(+), 33 deletions(-)

diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
index 2ca172cdc5c4..8c4f5d08270b 100644
--- a/arch/arm64/kvm/vgic-sys-reg-v3.c
+++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
@@ -23,30 +23,25 @@ static int set_gic_ctlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	 * Disallow restoring VM state if not supported by this
 	 * hardware.
 	 */
-	host_pri_bits = ((val & ICC_CTLR_EL1_PRI_BITS_MASK) >>
-			 ICC_CTLR_EL1_PRI_BITS_SHIFT) + 1;
+	host_pri_bits = FIELD_GET(ICC_CTLR_EL1_PRI_BITS_MASK, val) + 1;
 	if (host_pri_bits > vgic_v3_cpu->num_pri_bits)
 		return -EINVAL;
 
 	vgic_v3_cpu->num_pri_bits = host_pri_bits;
 
-	host_id_bits = (val & ICC_CTLR_EL1_ID_BITS_MASK) >>
-		ICC_CTLR_EL1_ID_BITS_SHIFT;
+	host_id_bits = FIELD_GET(ICC_CTLR_EL1_ID_BITS_MASK, val);
 	if (host_id_bits > vgic_v3_cpu->num_id_bits)
 		return -EINVAL;
 
 	vgic_v3_cpu->num_id_bits = host_id_bits;
 
-	host_seis = ((kvm_vgic_global_state.ich_vtr_el2 &
-		      ICH_VTR_SEIS_MASK) >> ICH_VTR_SEIS_SHIFT);
-	seis = (val & ICC_CTLR_EL1_SEIS_MASK) >>
-		ICC_CTLR_EL1_SEIS_SHIFT;
+	host_seis = FIELD_GET(ICH_VTR_SEIS_MASK, kvm_vgic_global_state.ich_vtr_el2);
+	seis = FIELD_GET(ICC_CTLR_EL1_SEIS_MASK, val);
 	if (host_seis != seis)
 		return -EINVAL;
 
-	host_a3v = ((kvm_vgic_global_state.ich_vtr_el2 &
-		     ICH_VTR_A3V_MASK) >> ICH_VTR_A3V_SHIFT);
-	a3v = (val & ICC_CTLR_EL1_A3V_MASK) >> ICC_CTLR_EL1_A3V_SHIFT;
+	host_a3v = FIELD_GET(ICH_VTR_A3V_MASK, kvm_vgic_global_state.ich_vtr_el2);
+	a3v = FIELD_GET(ICC_CTLR_EL1_A3V_MASK, val);
 	if (host_a3v != a3v)
 		return -EINVAL;
 
@@ -54,8 +49,8 @@ static int set_gic_ctlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	 * Here set VMCR.CTLR in ICC_CTLR_EL1 layout.
 	 * The vgic_set_vmcr() will convert to ICH_VMCR layout.
 	 */
-	vmcr.cbpr = (val & ICC_CTLR_EL1_CBPR_MASK) >> ICC_CTLR_EL1_CBPR_SHIFT;
-	vmcr.eoim = (val & ICC_CTLR_EL1_EOImode_MASK) >> ICC_CTLR_EL1_EOImode_SHIFT;
+	vmcr.cbpr = FIELD_GET(ICC_CTLR_EL1_CBPR_MASK, val);
+	vmcr.eoim = FIELD_GET(ICC_CTLR_EL1_EOImode_MASK, val);
 	vgic_set_vmcr(vcpu, &vmcr);
 
 	return 0;
@@ -70,20 +65,19 @@ static int get_gic_ctlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 
 	vgic_get_vmcr(vcpu, &vmcr);
 	val = 0;
-	val |= (vgic_v3_cpu->num_pri_bits - 1) << ICC_CTLR_EL1_PRI_BITS_SHIFT;
-	val |= vgic_v3_cpu->num_id_bits << ICC_CTLR_EL1_ID_BITS_SHIFT;
-	val |= ((kvm_vgic_global_state.ich_vtr_el2 &
-		 ICH_VTR_SEIS_MASK) >> ICH_VTR_SEIS_SHIFT) <<
-		ICC_CTLR_EL1_SEIS_SHIFT;
-	val |= ((kvm_vgic_global_state.ich_vtr_el2 &
-		 ICH_VTR_A3V_MASK) >> ICH_VTR_A3V_SHIFT) <<
-		ICC_CTLR_EL1_A3V_SHIFT;
+	val |= FIELD_PREP(ICC_CTLR_EL1_PRI_BITS_MASK, vgic_v3_cpu->num_pri_bits - 1);
+	val |= FIELD_PREP(ICC_CTLR_EL1_ID_BITS_MASK, vgic_v3_cpu->num_id_bits);
+	val |= FIELD_PREP(ICC_CTLR_EL1_SEIS_MASK,
+			  FIELD_GET(ICH_VTR_SEIS_MASK,
+				    kvm_vgic_global_state.ich_vtr_el2));
+	val |= FIELD_PREP(ICC_CTLR_EL1_A3V_MASK,
+			  FIELD_GET(ICH_VTR_A3V_MASK, kvm_vgic_global_state.ich_vtr_el2));
 	/*
 	 * The VMCR.CTLR value is in ICC_CTLR_EL1 layout.
 	 * Extract it directly using ICC_CTLR_EL1 reg definitions.
 	 */
-	val |= (vmcr.cbpr << ICC_CTLR_EL1_CBPR_SHIFT) & ICC_CTLR_EL1_CBPR_MASK;
-	val |= (vmcr.eoim << ICC_CTLR_EL1_EOImode_SHIFT) & ICC_CTLR_EL1_EOImode_MASK;
+	val |= FIELD_PREP(ICC_CTLR_EL1_CBPR_MASK, vmcr.cbpr);
+	val |= FIELD_PREP(ICC_CTLR_EL1_EOImode_MASK, vmcr.eoim);
 
 	*valp = val;
 
@@ -96,7 +90,7 @@ static int set_gic_pmr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	vmcr.pmr = (val & ICC_PMR_EL1_MASK) >> ICC_PMR_EL1_SHIFT;
+	vmcr.pmr = FIELD_GET(ICC_PMR_EL1_MASK, val);
 	vgic_set_vmcr(vcpu, &vmcr);
 
 	return 0;
@@ -108,7 +102,7 @@ static int get_gic_pmr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	*val = (vmcr.pmr << ICC_PMR_EL1_SHIFT) & ICC_PMR_EL1_MASK;
+	*val = FIELD_PREP(ICC_PMR_EL1_MASK, vmcr.pmr);
 
 	return 0;
 }
@@ -119,7 +113,7 @@ static int set_gic_bpr0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	vmcr.bpr = (val & ICC_BPR0_EL1_MASK) >> ICC_BPR0_EL1_SHIFT;
+	vmcr.bpr = FIELD_GET(ICC_BPR0_EL1_MASK, val);
 	vgic_set_vmcr(vcpu, &vmcr);
 
 	return 0;
@@ -131,7 +125,7 @@ static int get_gic_bpr0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	*val = (vmcr.bpr << ICC_BPR0_EL1_SHIFT) & ICC_BPR0_EL1_MASK;
+	*val = FIELD_PREP(ICC_BPR0_EL1_MASK, vmcr.bpr);
 
 	return 0;
 }
@@ -143,7 +137,7 @@ static int set_gic_bpr1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 
 	vgic_get_vmcr(vcpu, &vmcr);
 	if (!vmcr.cbpr) {
-		vmcr.abpr = (val & ICC_BPR1_EL1_MASK) >> ICC_BPR1_EL1_SHIFT;
+		vmcr.abpr = FIELD_GET(ICC_BPR1_EL1_MASK, val);
 		vgic_set_vmcr(vcpu, &vmcr);
 	}
 
@@ -157,7 +151,7 @@ static int get_gic_bpr1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 
 	vgic_get_vmcr(vcpu, &vmcr);
 	if (!vmcr.cbpr)
-		*val = (vmcr.abpr << ICC_BPR1_EL1_SHIFT) & ICC_BPR1_EL1_MASK;
+		*val = FIELD_PREP(ICC_BPR1_EL1_MASK, vmcr.abpr);
 	else
 		*val = min((vmcr.bpr + 1), 7U);
 
@@ -171,7 +165,7 @@ static int set_gic_grpen0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	vmcr.grpen0 = (val & ICC_IGRPEN0_EL1_MASK) >> ICC_IGRPEN0_EL1_SHIFT;
+	vmcr.grpen0 = FIELD_GET(ICC_IGRPEN0_EL1_MASK, val);
 	vgic_set_vmcr(vcpu, &vmcr);
 
 	return 0;
@@ -183,7 +177,7 @@ static int get_gic_grpen0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	*val = (vmcr.grpen0 << ICC_IGRPEN0_EL1_SHIFT) & ICC_IGRPEN0_EL1_MASK;
+	*val = FIELD_PREP(ICC_IGRPEN0_EL1_MASK, vmcr.grpen0);
 
 	return 0;
 }
@@ -194,7 +188,7 @@ static int set_gic_grpen1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	vmcr.grpen1 = (val & ICC_IGRPEN1_EL1_MASK) >> ICC_IGRPEN1_EL1_SHIFT;
+	vmcr.grpen1 = FIELD_GET(ICC_IGRPEN1_EL1_MASK, val);
 	vgic_set_vmcr(vcpu, &vmcr);
 
 	return 0;
@@ -206,7 +200,7 @@ static int get_gic_grpen1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	struct vgic_vmcr vmcr;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	*val = (vmcr.grpen1 << ICC_IGRPEN1_EL1_SHIFT) & ICC_IGRPEN1_EL1_MASK;
+	*val = FIELD_GET(ICC_IGRPEN1_EL1_MASK, vmcr.grpen1);
 
 	return 0;
 }
-- 
2.34.1


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Re: [PATCH 10/19] KVM: arm64: vgic-v3: Convert userspace accessors over to FIELD_GET/FIELD_PREP

[Reiji Watanabe]

On Wed, Jul 6, 2022 at 10:05 AM Marc Zyngier <maz@kernel.org> wrote:
>
> The GICv3 userspace accessors are all about dealing with conversion
> between fields from architectural registers and internal representations.
>
> However, and owing to the age of this code, the accessors use
> a combination of shift/mask that is hard to read. It is nonetheless
> easy to make it better by using the FIELD_{GET,PREP} macros that solely
> rely on a mask.
>
> This results in somewhat nicer looking code, and is probably easier
> to maintain.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Reiji Watanabe <reijiw@google.com>

_______________________________________________
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[PATCH 11/19] KVM: arm64: vgic-v3: Use u32 to manage the line level from userspace

[Marc Zyngier]

Despite the userspace ABI clearly defining the bits dealt with by
KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO as a __u32, the kernel uses a u64.

Use a u32 to match the userspace ABI, which will subsequently lead
to some simplifications.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic/vgic-kvm-device.c | 6 +++++-
 arch/arm64/kvm/vgic/vgic-mmio-v3.c    | 2 +-
 arch/arm64/kvm/vgic/vgic-mmio.c       | 6 +++---
 arch/arm64/kvm/vgic/vgic-mmio.h       | 4 ++--
 arch/arm64/kvm/vgic/vgic.h            | 2 +-
 5 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
index d8269300632d..01285ee5cdf0 100644
--- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
+++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
@@ -570,10 +570,14 @@ static int vgic_v3_attr_regs_access(struct kvm_device *dev,
 		info = (attr->attr & KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_MASK) >>
 			KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_SHIFT;
 		if (info == VGIC_LEVEL_INFO_LINE_LEVEL) {
+			if (is_write)
+				tmp32 = *reg;
 			intid = attr->attr &
 				KVM_DEV_ARM_VGIC_LINE_LEVEL_INTID_MASK;
 			ret = vgic_v3_line_level_info_uaccess(vcpu, is_write,
-							      intid, reg);
+							      intid, &tmp32);
+			if (!is_write)
+				*reg = tmp32;
 		} else {
 			ret = -EINVAL;
 		}
diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
index a2ff73899976..91201f743033 100644
--- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
@@ -1154,7 +1154,7 @@ int vgic_v3_redist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 }
 
 int vgic_v3_line_level_info_uaccess(struct kvm_vcpu *vcpu, bool is_write,
-				    u32 intid, u64 *val)
+				    u32 intid, u32 *val)
 {
 	if (intid % 32)
 		return -EINVAL;
diff --git a/arch/arm64/kvm/vgic/vgic-mmio.c b/arch/arm64/kvm/vgic/vgic-mmio.c
index 997d0fce2088..b32d434c1d4a 100644
--- a/arch/arm64/kvm/vgic/vgic-mmio.c
+++ b/arch/arm64/kvm/vgic/vgic-mmio.c
@@ -775,10 +775,10 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
 	}
 }
 
-u64 vgic_read_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid)
+u32 vgic_read_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid)
 {
 	int i;
-	u64 val = 0;
+	u32 val = 0;
 	int nr_irqs = vcpu->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
 
 	for (i = 0; i < 32; i++) {
@@ -798,7 +798,7 @@ u64 vgic_read_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid)
 }
 
 void vgic_write_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid,
-				    const u64 val)
+				    const u32 val)
 {
 	int i;
 	int nr_irqs = vcpu->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
diff --git a/arch/arm64/kvm/vgic/vgic-mmio.h b/arch/arm64/kvm/vgic/vgic-mmio.h
index 6082d4b66d39..5b490a4dfa5e 100644
--- a/arch/arm64/kvm/vgic/vgic-mmio.h
+++ b/arch/arm64/kvm/vgic/vgic-mmio.h
@@ -207,10 +207,10 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
 int vgic_uaccess(struct kvm_vcpu *vcpu, struct vgic_io_device *dev,
 		 bool is_write, int offset, u32 *val);
 
-u64 vgic_read_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid);
+u32 vgic_read_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid);
 
 void vgic_write_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid,
-				    const u64 val);
+				    const u32 val);
 
 unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev);
 
diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h
index c23118467a35..0c8da72953f0 100644
--- a/arch/arm64/kvm/vgic/vgic.h
+++ b/arch/arm64/kvm/vgic/vgic.h
@@ -249,7 +249,7 @@ int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu,
 				struct kvm_device_attr *attr, bool is_write);
 int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
 int vgic_v3_line_level_info_uaccess(struct kvm_vcpu *vcpu, bool is_write,
-				    u32 intid, u64 *val);
+				    u32 intid, u32 *val);
 int kvm_register_vgic_device(unsigned long type);
 void vgic_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
 void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
-- 
2.34.1


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Re: [PATCH 11/19] KVM: arm64: vgic-v3: Use u32 to manage the line level from userspace

[Reiji Watanabe]

On Wed, Jul 6, 2022 at 10:05 AM Marc Zyngier <maz@kernel.org> wrote:
>
> Despite the userspace ABI clearly defining the bits dealt with by
> KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO as a __u32, the kernel uses a u64.
>
> Use a u32 to match the userspace ABI, which will subsequently lead
> to some simplifications.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Reiji Watanabe <reijiw@google.com>

_______________________________________________
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[PATCH 12/19] KVM: arm64: vgic-v3: Consolidate userspace access for MMIO registers

[Marc Zyngier]

For userspace accesses to GICv3 MMIO registers (and related data),
vgic_v3_{get,set}_attr are littered with {get,put}_user() calls,
making it hard to audit and reason about.

Consolidate all userspace accesses in vgic_v3_attr_regs_access(),
makeing the code far simpler to audit.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic/vgic-kvm-device.c | 104 ++++++++++----------------
 1 file changed, 38 insertions(+), 66 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
index 01285ee5cdf0..925875722027 100644
--- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
+++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
@@ -512,18 +512,18 @@ int vgic_v3_parse_attr(struct kvm_device *dev, struct kvm_device_attr *attr,
  *
  * @dev:      kvm device handle
  * @attr:     kvm device attribute
- * @reg:      address the value is read or written
  * @is_write: true if userspace is writing a register
  */
 static int vgic_v3_attr_regs_access(struct kvm_device *dev,
 				    struct kvm_device_attr *attr,
-				    u64 *reg, bool is_write)
+				    bool is_write)
 {
 	struct vgic_reg_attr reg_attr;
 	gpa_t addr;
 	struct kvm_vcpu *vcpu;
+	bool uaccess;
+	u32 val;
 	int ret;
-	u32 tmp32;
 
 	ret = vgic_v3_parse_attr(dev, attr, &reg_attr);
 	if (ret)
@@ -532,6 +532,21 @@ static int vgic_v3_attr_regs_access(struct kvm_device *dev,
 	vcpu = reg_attr.vcpu;
 	addr = reg_attr.addr;
 
+	switch (attr->group) {
+	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
+		/* Sysregs uaccess is performed by the sysreg handling code */
+		uaccess = false;
+		break;
+	default:
+		uaccess = true;
+	}
+
+	if (uaccess && is_write) {
+		u32 __user *uaddr = (u32 __user *)(unsigned long)attr->addr;
+		if (get_user(val, uaddr))
+			return -EFAULT;
+	}
+
 	mutex_lock(&dev->kvm->lock);
 
 	if (unlikely(!vgic_initialized(dev->kvm))) {
@@ -546,20 +561,10 @@ static int vgic_v3_attr_regs_access(struct kvm_device *dev,
 
 	switch (attr->group) {
 	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
-		if (is_write)
-			tmp32 = *reg;
-
-		ret = vgic_v3_dist_uaccess(vcpu, is_write, addr, &tmp32);
-		if (!is_write)
-			*reg = tmp32;
+		ret = vgic_v3_dist_uaccess(vcpu, is_write, addr, &val);
 		break;
 	case KVM_DEV_ARM_VGIC_GRP_REDIST_REGS:
-		if (is_write)
-			tmp32 = *reg;
-
-		ret = vgic_v3_redist_uaccess(vcpu, is_write, addr, &tmp32);
-		if (!is_write)
-			*reg = tmp32;
+		ret = vgic_v3_redist_uaccess(vcpu, is_write, addr, &val);
 		break;
 	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
 		ret = vgic_v3_cpu_sysregs_uaccess(vcpu, attr, is_write);
@@ -570,14 +575,10 @@ static int vgic_v3_attr_regs_access(struct kvm_device *dev,
 		info = (attr->attr & KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_MASK) >>
 			KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_SHIFT;
 		if (info == VGIC_LEVEL_INFO_LINE_LEVEL) {
-			if (is_write)
-				tmp32 = *reg;
 			intid = attr->attr &
 				KVM_DEV_ARM_VGIC_LINE_LEVEL_INTID_MASK;
 			ret = vgic_v3_line_level_info_uaccess(vcpu, is_write,
-							      intid, &tmp32);
-			if (!is_write)
-				*reg = tmp32;
+							      intid, &val);
 		} else {
 			ret = -EINVAL;
 		}
@@ -591,6 +592,13 @@ static int vgic_v3_attr_regs_access(struct kvm_device *dev,
 	unlock_all_vcpus(dev->kvm);
 out:
 	mutex_unlock(&dev->kvm->lock);
+
+	if (!ret && uaccess && !is_write) {
+		u32 __user *uaddr = (u32 __user *)(unsigned long)attr->addr;
+		if (put_user(val, uaddr))
+			ret = -EFAULT;
+	}
+
 	return ret;
 }
 
@@ -605,30 +613,12 @@ static int vgic_v3_set_attr(struct kvm_device *dev,
 
 	switch (attr->group) {
 	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
-	case KVM_DEV_ARM_VGIC_GRP_REDIST_REGS: {
-		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
-		u32 tmp32;
-		u64 reg;
-
-		if (get_user(tmp32, uaddr))
-			return -EFAULT;
-
-		reg = tmp32;
-		return vgic_v3_attr_regs_access(dev, attr, &reg, true);
-	}
+	case KVM_DEV_ARM_VGIC_GRP_REDIST_REGS:
+		return vgic_v3_attr_regs_access(dev, attr, true);
 	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
-		return vgic_v3_attr_regs_access(dev, attr, NULL, true);
-	case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO: {
-		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
-		u64 reg;
-		u32 tmp32;
-
-		if (get_user(tmp32, uaddr))
-			return -EFAULT;
-
-		reg = tmp32;
-		return vgic_v3_attr_regs_access(dev, attr, &reg, true);
-	}
+		return vgic_v3_attr_regs_access(dev, attr, true);
+	case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO:
+		return vgic_v3_attr_regs_access(dev, attr, true);
 	case KVM_DEV_ARM_VGIC_GRP_CTRL: {
 		int ret;
 
@@ -662,30 +652,12 @@ static int vgic_v3_get_attr(struct kvm_device *dev,
 
 	switch (attr->group) {
 	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
-	case KVM_DEV_ARM_VGIC_GRP_REDIST_REGS: {
-		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
-		u64 reg;
-		u32 tmp32;
-
-		ret = vgic_v3_attr_regs_access(dev, attr, &reg, false);
-		if (ret)
-			return ret;
-		tmp32 = reg;
-		return put_user(tmp32, uaddr);
-	}
+	case KVM_DEV_ARM_VGIC_GRP_REDIST_REGS:
+		return vgic_v3_attr_regs_access(dev, attr, false);
 	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
-		return vgic_v3_attr_regs_access(dev, attr, NULL, false);
-	case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO: {
-		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
-		u64 reg;
-		u32 tmp32;
-
-		ret = vgic_v3_attr_regs_access(dev, attr, &reg, false);
-		if (ret)
-			return ret;
-		tmp32 = reg;
-		return put_user(tmp32, uaddr);
-	}
+		return vgic_v3_attr_regs_access(dev, attr, false);
+	case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO:
+		return vgic_v3_attr_regs_access(dev, attr, false);
 	}
 	return -ENXIO;
 }
-- 
2.34.1


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Re: [PATCH 12/19] KVM: arm64: vgic-v3: Consolidate userspace access for MMIO registers

[Reiji Watanabe]

On Wed, Jul 6, 2022 at 10:05 AM Marc Zyngier <maz@kernel.org> wrote:
>
> For userspace accesses to GICv3 MMIO registers (and related data),
> vgic_v3_{get,set}_attr are littered with {get,put}_user() calls,
> making it hard to audit and reason about.
>
> Consolidate all userspace accesses in vgic_v3_attr_regs_access(),
> makeing the code far simpler to audit.

Nit: s/makeing/making/

>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Reiji Watanabe <reijiw@google.com>

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[PATCH 13/19] KVM: arm64: vgic-v2: Consolidate userspace access for MMIO registers

[Marc Zyngier]

Align the GICv2 MMIO accesses from userspace with the way the GICv3
code is now structured.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic/vgic-kvm-device.c | 40 ++++++++++++---------------
 1 file changed, 18 insertions(+), 22 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
index 925875722027..ddead333c232 100644
--- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
+++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
@@ -348,17 +348,18 @@ bool lock_all_vcpus(struct kvm *kvm)
  *
  * @dev:      kvm device handle
  * @attr:     kvm device attribute
- * @reg:      address the value is read or written
  * @is_write: true if userspace is writing a register
  */
 static int vgic_v2_attr_regs_access(struct kvm_device *dev,
 				    struct kvm_device_attr *attr,
-				    u32 *reg, bool is_write)
+				    bool is_write)
 {
+	u32 __user *uaddr = (u32 __user *)(unsigned long)attr->addr;
 	struct vgic_reg_attr reg_attr;
 	gpa_t addr;
 	struct kvm_vcpu *vcpu;
 	int ret;
+	u32 val;
 
 	ret = vgic_v2_parse_attr(dev, attr, &reg_attr);
 	if (ret)
@@ -367,6 +368,10 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
 	vcpu = reg_attr.vcpu;
 	addr = reg_attr.addr;
 
+	if (is_write)
+		if (get_user(val, uaddr))
+			return -EFAULT;
+
 	mutex_lock(&dev->kvm->lock);
 
 	ret = vgic_init(dev->kvm);
@@ -380,10 +385,10 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
 
 	switch (attr->group) {
 	case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
-		ret = vgic_v2_cpuif_uaccess(vcpu, is_write, addr, reg);
+		ret = vgic_v2_cpuif_uaccess(vcpu, is_write, addr, &val);
 		break;
 	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
-		ret = vgic_v2_dist_uaccess(vcpu, is_write, addr, reg);
+		ret = vgic_v2_dist_uaccess(vcpu, is_write, addr, &val);
 		break;
 	default:
 		ret = -EINVAL;
@@ -393,6 +398,11 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
 	unlock_all_vcpus(dev->kvm);
 out:
 	mutex_unlock(&dev->kvm->lock);
+
+	if (!ret && !is_write)
+		if (put_user(val, uaddr))
+			ret = -EFAULT;
+
 	return ret;
 }
 
@@ -407,15 +417,8 @@ static int vgic_v2_set_attr(struct kvm_device *dev,
 
 	switch (attr->group) {
 	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
-	case KVM_DEV_ARM_VGIC_GRP_CPU_REGS: {
-		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
-		u32 reg;
-
-		if (get_user(reg, uaddr))
-			return -EFAULT;
-
-		return vgic_v2_attr_regs_access(dev, attr, &reg, true);
-	}
+	case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
+		return vgic_v2_attr_regs_access(dev, attr, true);
 	}
 
 	return -ENXIO;
@@ -432,15 +435,8 @@ static int vgic_v2_get_attr(struct kvm_device *dev,
 
 	switch (attr->group) {
 	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
-	case KVM_DEV_ARM_VGIC_GRP_CPU_REGS: {
-		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
-		u32 reg = 0;
-
-		ret = vgic_v2_attr_regs_access(dev, attr, &reg, false);
-		if (ret)
-			return ret;
-		return put_user(reg, uaddr);
-	}
+	case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
+		return vgic_v2_attr_regs_access(dev, attr, false);
 	}
 
 	return -ENXIO;
-- 
2.34.1


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Re: [PATCH 13/19] KVM: arm64: vgic-v2: Consolidate userspace access for MMIO registers

[Reiji Watanabe]

Hi Marc,

On Wed, Jul 6, 2022 at 10:05 AM Marc Zyngier <maz@kernel.org> wrote:
>
> Align the GICv2 MMIO accesses from userspace with the way the GICv3
> code is now structured.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/vgic/vgic-kvm-device.c | 40 ++++++++++++---------------
>  1 file changed, 18 insertions(+), 22 deletions(-)
>
> diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> index 925875722027..ddead333c232 100644
> --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
> +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> @@ -348,17 +348,18 @@ bool lock_all_vcpus(struct kvm *kvm)
>   *
>   * @dev:      kvm device handle
>   * @attr:     kvm device attribute
> - * @reg:      address the value is read or written
>   * @is_write: true if userspace is writing a register
>   */
>  static int vgic_v2_attr_regs_access(struct kvm_device *dev,
>                                     struct kvm_device_attr *attr,
> -                                   u32 *reg, bool is_write)
> +                                   bool is_write)
>  {
> +       u32 __user *uaddr = (u32 __user *)(unsigned long)attr->addr;
>         struct vgic_reg_attr reg_attr;
>         gpa_t addr;
>         struct kvm_vcpu *vcpu;
>         int ret;
> +       u32 val;
>
>         ret = vgic_v2_parse_attr(dev, attr, &reg_attr);
>         if (ret)
> @@ -367,6 +368,10 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
>         vcpu = reg_attr.vcpu;
>         addr = reg_attr.addr;
>
> +       if (is_write)
> +               if (get_user(val, uaddr))
> +                       return -EFAULT;
> +
>         mutex_lock(&dev->kvm->lock);
>
>         ret = vgic_init(dev->kvm);
> @@ -380,10 +385,10 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
>
>         switch (attr->group) {
>         case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
> -               ret = vgic_v2_cpuif_uaccess(vcpu, is_write, addr, reg);
> +               ret = vgic_v2_cpuif_uaccess(vcpu, is_write, addr, &val);
>                 break;
>         case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> -               ret = vgic_v2_dist_uaccess(vcpu, is_write, addr, reg);
> +               ret = vgic_v2_dist_uaccess(vcpu, is_write, addr, &val);
>                 break;
>         default:
>                 ret = -EINVAL;
> @@ -393,6 +398,11 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
>         unlock_all_vcpus(dev->kvm);
>  out:
>         mutex_unlock(&dev->kvm->lock);
> +
> +       if (!ret && !is_write)
> +               if (put_user(val, uaddr))
> +                       ret = -EFAULT;
> +
>         return ret;
>  }
>
> @@ -407,15 +417,8 @@ static int vgic_v2_set_attr(struct kvm_device *dev,
>
>         switch (attr->group) {
>         case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> -       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS: {
> -               u32 __user *uaddr = (u32 __user *)(long)attr->addr;
> -               u32 reg;
> -
> -               if (get_user(reg, uaddr))
> -                       return -EFAULT;
> -
> -               return vgic_v2_attr_regs_access(dev, attr, &reg, true);
> -       }
> +       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
> +               return vgic_v2_attr_regs_access(dev, attr, true);
>         }
>
>         return -ENXIO;
> @@ -432,15 +435,8 @@ static int vgic_v2_get_attr(struct kvm_device *dev,
>
>         switch (attr->group) {
>         case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> -       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS: {
> -               u32 __user *uaddr = (u32 __user *)(long)attr->addr;
> -               u32 reg = 0;
> -
> -               ret = vgic_v2_attr_regs_access(dev, attr, &reg, false);
> -               if (ret)
> -                       return ret;
> -               return put_user(reg, uaddr);
> -       }
> +       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
> +               return vgic_v2_attr_regs_access(dev, attr, false);
>         }
>
>         return -ENXIO;

For vgic_v2_{set,get}_attr(), perhaps it might be even simpler
to call vgic_{set,get}_common_attr() from the "default" case
of "switch (attr->group)".
This is not directly related to this patch though:)

Reviewed-by: Reiji Watanabe <reijiw@google.com>

Thank you,
Reiji

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Re: [PATCH 13/19] KVM: arm64: vgic-v2: Consolidate userspace access for MMIO registers

[Marc Zyngier]

On Thu, 14 Jul 2022 05:43:27 +0100,
Reiji Watanabe <reijiw@google.com> wrote:
> 
> Hi Marc,
> 
> On Wed, Jul 6, 2022 at 10:05 AM Marc Zyngier <maz@kernel.org> wrote:
> >
> > Align the GICv2 MMIO accesses from userspace with the way the GICv3
> > code is now structured.
> >
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > ---
> >  arch/arm64/kvm/vgic/vgic-kvm-device.c | 40 ++++++++++++---------------
> >  1 file changed, 18 insertions(+), 22 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > index 925875722027..ddead333c232 100644
> > --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > @@ -348,17 +348,18 @@ bool lock_all_vcpus(struct kvm *kvm)
> >   *
> >   * @dev:      kvm device handle
> >   * @attr:     kvm device attribute
> > - * @reg:      address the value is read or written
> >   * @is_write: true if userspace is writing a register
> >   */
> >  static int vgic_v2_attr_regs_access(struct kvm_device *dev,
> >                                     struct kvm_device_attr *attr,
> > -                                   u32 *reg, bool is_write)
> > +                                   bool is_write)
> >  {
> > +       u32 __user *uaddr = (u32 __user *)(unsigned long)attr->addr;
> >         struct vgic_reg_attr reg_attr;
> >         gpa_t addr;
> >         struct kvm_vcpu *vcpu;
> >         int ret;
> > +       u32 val;
> >
> >         ret = vgic_v2_parse_attr(dev, attr, &reg_attr);
> >         if (ret)
> > @@ -367,6 +368,10 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
> >         vcpu = reg_attr.vcpu;
> >         addr = reg_attr.addr;
> >
> > +       if (is_write)
> > +               if (get_user(val, uaddr))
> > +                       return -EFAULT;
> > +
> >         mutex_lock(&dev->kvm->lock);
> >
> >         ret = vgic_init(dev->kvm);
> > @@ -380,10 +385,10 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
> >
> >         switch (attr->group) {
> >         case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
> > -               ret = vgic_v2_cpuif_uaccess(vcpu, is_write, addr, reg);
> > +               ret = vgic_v2_cpuif_uaccess(vcpu, is_write, addr, &val);
> >                 break;
> >         case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> > -               ret = vgic_v2_dist_uaccess(vcpu, is_write, addr, reg);
> > +               ret = vgic_v2_dist_uaccess(vcpu, is_write, addr, &val);
> >                 break;
> >         default:
> >                 ret = -EINVAL;
> > @@ -393,6 +398,11 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
> >         unlock_all_vcpus(dev->kvm);
> >  out:
> >         mutex_unlock(&dev->kvm->lock);
> > +
> > +       if (!ret && !is_write)
> > +               if (put_user(val, uaddr))
> > +                       ret = -EFAULT;
> > +
> >         return ret;
> >  }
> >
> > @@ -407,15 +417,8 @@ static int vgic_v2_set_attr(struct kvm_device *dev,
> >
> >         switch (attr->group) {
> >         case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> > -       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS: {
> > -               u32 __user *uaddr = (u32 __user *)(long)attr->addr;
> > -               u32 reg;
> > -
> > -               if (get_user(reg, uaddr))
> > -                       return -EFAULT;
> > -
> > -               return vgic_v2_attr_regs_access(dev, attr, &reg, true);
> > -       }
> > +       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
> > +               return vgic_v2_attr_regs_access(dev, attr, true);
> >         }
> >
> >         return -ENXIO;
> > @@ -432,15 +435,8 @@ static int vgic_v2_get_attr(struct kvm_device *dev,
> >
> >         switch (attr->group) {
> >         case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> > -       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS: {
> > -               u32 __user *uaddr = (u32 __user *)(long)attr->addr;
> > -               u32 reg = 0;
> > -
> > -               ret = vgic_v2_attr_regs_access(dev, attr, &reg, false);
> > -               if (ret)
> > -                       return ret;
> > -               return put_user(reg, uaddr);
> > -       }
> > +       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
> > +               return vgic_v2_attr_regs_access(dev, attr, false);
> >         }
> >
> >         return -ENXIO;
> 
> For vgic_v2_{set,get}_attr(), perhaps it might be even simpler
> to call vgic_{set,get}_common_attr() from the "default" case
> of "switch (attr->group)".
> This is not directly related to this patch though:)

Indeed. This also applies to v3, and there is a couple more cleanups
that can be added. I'll add that as an extra patch, as the result is
rather nice.

> Reviewed-by: Reiji Watanabe <reijiw@google.com>

Thanks,

	M.

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[PATCH 14/19] KVM: arm64: vgic: Use {get,put}_user() instead of copy_{from.to}_user

[Marc Zyngier]

Tidy-up vgic_get_common_attr() and vgic_set_common_attr() to use
{get,put}_user() instead of the more complex (and less type-safe)
copy_{from,to}_user().

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic/vgic-kvm-device.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
index ddead333c232..fbbd0338c782 100644
--- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
+++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
@@ -170,7 +170,7 @@ static int vgic_set_common_attr(struct kvm_device *dev,
 		u64 addr;
 		unsigned long type = (unsigned long)attr->attr;
 
-		if (copy_from_user(&addr, uaddr, sizeof(addr)))
+		if (get_user(addr, uaddr))
 			return -EFAULT;
 
 		r = kvm_vgic_addr(dev->kvm, type, &addr, true);
@@ -233,14 +233,14 @@ static int vgic_get_common_attr(struct kvm_device *dev,
 		u64 addr;
 		unsigned long type = (unsigned long)attr->attr;
 
-		if (copy_from_user(&addr, uaddr, sizeof(addr)))
+		if (get_user(addr, uaddr))
 			return -EFAULT;
 
 		r = kvm_vgic_addr(dev->kvm, type, &addr, false);
 		if (r)
 			return (r == -ENODEV) ? -ENXIO : r;
 
-		if (copy_to_user(uaddr, &addr, sizeof(addr)))
+		if (put_user(addr, uaddr))
 			return -EFAULT;
 		break;
 	}
-- 
2.34.1


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Re: [PATCH 14/19] KVM: arm64: vgic: Use {get, put}_user() instead of copy_{from.to}_user

[Reiji Watanabe]

On Wed, Jul 6, 2022 at 10:05 AM Marc Zyngier <maz@kernel.org> wrote:
>
> Tidy-up vgic_get_common_attr() and vgic_set_common_attr() to use
> {get,put}_user() instead of the more complex (and less type-safe)
> copy_{from,to}_user().
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Reiji Watanabe <reijiw@google.com>

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[PATCH 15/19] KVM: arm64: vgic-v2: Add helper for legacy dist/cpuif base address setting

[Marc Zyngier]

We carry a legacy interface to set the base addresses for GICv2.
As this is currently plumbed into the same handling code as
the modern interface, it limits the evolution we can make there.

Add a helper dedicated to this handling, with a view of maybe
removing this in the future.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/arm.c                  | 11 ++-------
 arch/arm64/kvm/vgic/vgic-kvm-device.c | 32 +++++++++++++++++++++++++++
 include/kvm/arm_vgic.h                |  1 +
 3 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 83a7f61354d3..bf39570c0aef 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1414,18 +1414,11 @@ void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
 static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
 					struct kvm_arm_device_addr *dev_addr)
 {
-	unsigned long dev_id, type;
-
-	dev_id = (dev_addr->id & KVM_ARM_DEVICE_ID_MASK) >>
-		KVM_ARM_DEVICE_ID_SHIFT;
-	type = (dev_addr->id & KVM_ARM_DEVICE_TYPE_MASK) >>
-		KVM_ARM_DEVICE_TYPE_SHIFT;
-
-	switch (dev_id) {
+	switch (FIELD_GET(KVM_ARM_DEVICE_ID_MASK, dev_addr->id)) {
 	case KVM_ARM_DEVICE_VGIC_V2:
 		if (!vgic_present)
 			return -ENXIO;
-		return kvm_vgic_addr(kvm, type, &dev_addr->addr, true);
+		return kvm_set_legacy_vgic_v2_addr(kvm, dev_addr);
 	default:
 		return -ENODEV;
 	}
diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
index fbbd0338c782..0dfd277b9058 100644
--- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
+++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
@@ -41,6 +41,38 @@ static int vgic_check_type(struct kvm *kvm, int type_needed)
 		return 0;
 }
 
+int kvm_set_legacy_vgic_v2_addr(struct kvm *kvm, struct kvm_arm_device_addr *dev_addr)
+{
+	struct vgic_dist *vgic = &kvm->arch.vgic;
+	int r;
+
+	mutex_lock(&kvm->lock);
+	switch (FIELD_GET(KVM_ARM_DEVICE_ID_MASK, dev_addr->id)) {
+	case KVM_VGIC_V2_ADDR_TYPE_DIST:
+		r = vgic_check_type(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
+		if (!r)
+			r = vgic_check_iorange(kvm, vgic->vgic_dist_base, dev_addr->addr,
+					       SZ_4K, KVM_VGIC_V2_DIST_SIZE);
+		if (!r)
+			vgic->vgic_dist_base = dev_addr->addr;
+		break;
+	case KVM_VGIC_V2_ADDR_TYPE_CPU:
+		r = vgic_check_type(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
+		if (!r)
+			r = vgic_check_iorange(kvm, vgic->vgic_cpu_base, dev_addr->addr,
+					       SZ_4K, KVM_VGIC_V2_CPU_SIZE);
+		if (!r)
+			vgic->vgic_cpu_base = dev_addr->addr;
+		break;
+	default:
+		r = -ENODEV;
+	}
+
+	mutex_unlock(&kvm->lock);
+
+	return r;
+}
+
 /**
  * kvm_vgic_addr - set or get vgic VM base addresses
  * @kvm:   pointer to the vm struct
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 2d8f2e90edc2..f79cce67563e 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -365,6 +365,7 @@ extern struct static_key_false vgic_v2_cpuif_trap;
 extern struct static_key_false vgic_v3_cpuif_trap;
 
 int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write);
+int kvm_set_legacy_vgic_v2_addr(struct kvm *kvm, struct kvm_arm_device_addr *dev_addr);
 void kvm_vgic_early_init(struct kvm *kvm);
 int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu);
 int kvm_vgic_create(struct kvm *kvm, u32 type);
-- 
2.34.1


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Re: [PATCH 15/19] KVM: arm64: vgic-v2: Add helper for legacy dist/cpuif base address setting

[Reiji Watanabe]

Hi Marc,

On Wed, Jul 6, 2022 at 10:05 AM Marc Zyngier <maz@kernel.org> wrote:
>
> We carry a legacy interface to set the base addresses for GICv2.
> As this is currently plumbed into the same handling code as
> the modern interface, it limits the evolution we can make there.
>
> Add a helper dedicated to this handling, with a view of maybe
> removing this in the future.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/arm.c                  | 11 ++-------
>  arch/arm64/kvm/vgic/vgic-kvm-device.c | 32 +++++++++++++++++++++++++++
>  include/kvm/arm_vgic.h                |  1 +
>  3 files changed, 35 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 83a7f61354d3..bf39570c0aef 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -1414,18 +1414,11 @@ void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
>  static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
>                                         struct kvm_arm_device_addr *dev_addr)
>  {
> -       unsigned long dev_id, type;
> -
> -       dev_id = (dev_addr->id & KVM_ARM_DEVICE_ID_MASK) >>
> -               KVM_ARM_DEVICE_ID_SHIFT;
> -       type = (dev_addr->id & KVM_ARM_DEVICE_TYPE_MASK) >>
> -               KVM_ARM_DEVICE_TYPE_SHIFT;
> -
> -       switch (dev_id) {
> +       switch (FIELD_GET(KVM_ARM_DEVICE_ID_MASK, dev_addr->id)) {
>         case KVM_ARM_DEVICE_VGIC_V2:
>                 if (!vgic_present)
>                         return -ENXIO;
> -               return kvm_vgic_addr(kvm, type, &dev_addr->addr, true);
> +               return kvm_set_legacy_vgic_v2_addr(kvm, dev_addr);
>         default:
>                 return -ENODEV;
>         }
> diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> index fbbd0338c782..0dfd277b9058 100644
> --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
> +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> @@ -41,6 +41,38 @@ static int vgic_check_type(struct kvm *kvm, int type_needed)
>                 return 0;
>  }
>
> +int kvm_set_legacy_vgic_v2_addr(struct kvm *kvm, struct kvm_arm_device_addr *dev_addr)
> +{
> +       struct vgic_dist *vgic = &kvm->arch.vgic;
> +       int r;
> +
> +       mutex_lock(&kvm->lock);
> +       switch (FIELD_GET(KVM_ARM_DEVICE_ID_MASK, dev_addr->id)) {

Shouldn't this be KVM_ARM_DEVICE_TYPE_MASK (not KVM_ARM_DEVICE_ID_MASK) ?

Thank you,
Reiji


> +       case KVM_VGIC_V2_ADDR_TYPE_DIST:
> +               r = vgic_check_type(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
> +               if (!r)
> +                       r = vgic_check_iorange(kvm, vgic->vgic_dist_base, dev_addr->addr,
> +                                              SZ_4K, KVM_VGIC_V2_DIST_SIZE);
> +               if (!r)
> +                       vgic->vgic_dist_base = dev_addr->addr;
> +               break;
> +       case KVM_VGIC_V2_ADDR_TYPE_CPU:
> +               r = vgic_check_type(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
> +               if (!r)
> +                       r = vgic_check_iorange(kvm, vgic->vgic_cpu_base, dev_addr->addr,
> +                                              SZ_4K, KVM_VGIC_V2_CPU_SIZE);
> +               if (!r)
> +                       vgic->vgic_cpu_base = dev_addr->addr;
> +               break;
> +       default:
> +               r = -ENODEV;
> +       }
> +
> +       mutex_unlock(&kvm->lock);
> +
> +       return r;
> +}
> +
>  /**
>   * kvm_vgic_addr - set or get vgic VM base addresses
>   * @kvm:   pointer to the vm struct
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index 2d8f2e90edc2..f79cce67563e 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -365,6 +365,7 @@ extern struct static_key_false vgic_v2_cpuif_trap;
>  extern struct static_key_false vgic_v3_cpuif_trap;
>
>  int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write);
> +int kvm_set_legacy_vgic_v2_addr(struct kvm *kvm, struct kvm_arm_device_addr *dev_addr);
>  void kvm_vgic_early_init(struct kvm *kvm);
>  int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu);
>  int kvm_vgic_create(struct kvm *kvm, u32 type);
> --
> 2.34.1
>
> _______________________________________________
> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

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Re: [PATCH 15/19] KVM: arm64: vgic-v2: Add helper for legacy dist/cpuif base address setting

[Marc Zyngier]

On Thu, 14 Jul 2022 07:37:25 +0100,
Reiji Watanabe <reijiw@google.com> wrote:
> 
> Hi Marc,
> 
> On Wed, Jul 6, 2022 at 10:05 AM Marc Zyngier <maz@kernel.org> wrote:
> >
> > We carry a legacy interface to set the base addresses for GICv2.
> > As this is currently plumbed into the same handling code as
> > the modern interface, it limits the evolution we can make there.
> >
> > Add a helper dedicated to this handling, with a view of maybe
> > removing this in the future.
> >
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > ---
> >  arch/arm64/kvm/arm.c                  | 11 ++-------
> >  arch/arm64/kvm/vgic/vgic-kvm-device.c | 32 +++++++++++++++++++++++++++
> >  include/kvm/arm_vgic.h                |  1 +
> >  3 files changed, 35 insertions(+), 9 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> > index 83a7f61354d3..bf39570c0aef 100644
> > --- a/arch/arm64/kvm/arm.c
> > +++ b/arch/arm64/kvm/arm.c
> > @@ -1414,18 +1414,11 @@ void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
> >  static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
> >                                         struct kvm_arm_device_addr *dev_addr)
> >  {
> > -       unsigned long dev_id, type;
> > -
> > -       dev_id = (dev_addr->id & KVM_ARM_DEVICE_ID_MASK) >>
> > -               KVM_ARM_DEVICE_ID_SHIFT;
> > -       type = (dev_addr->id & KVM_ARM_DEVICE_TYPE_MASK) >>
> > -               KVM_ARM_DEVICE_TYPE_SHIFT;
> > -
> > -       switch (dev_id) {
> > +       switch (FIELD_GET(KVM_ARM_DEVICE_ID_MASK, dev_addr->id)) {
> >         case KVM_ARM_DEVICE_VGIC_V2:
> >                 if (!vgic_present)
> >                         return -ENXIO;
> > -               return kvm_vgic_addr(kvm, type, &dev_addr->addr, true);
> > +               return kvm_set_legacy_vgic_v2_addr(kvm, dev_addr);
> >         default:
> >                 return -ENODEV;
> >         }
> > diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > index fbbd0338c782..0dfd277b9058 100644
> > --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > @@ -41,6 +41,38 @@ static int vgic_check_type(struct kvm *kvm, int type_needed)
> >                 return 0;
> >  }
> >
> > +int kvm_set_legacy_vgic_v2_addr(struct kvm *kvm, struct kvm_arm_device_addr *dev_addr)
> > +{
> > +       struct vgic_dist *vgic = &kvm->arch.vgic;
> > +       int r;
> > +
> > +       mutex_lock(&kvm->lock);
> > +       switch (FIELD_GET(KVM_ARM_DEVICE_ID_MASK, dev_addr->id)) {
> 
> Shouldn't this be KVM_ARM_DEVICE_TYPE_MASK (not KVM_ARM_DEVICE_ID_MASK) ?

Damn, you just ruined my attempt at deprecating this API ;-). More
seriously, thanks for catching this one!

	M.

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Re: [PATCH 15/19] KVM: arm64: vgic-v2: Add helper for legacy dist/cpuif base address setting

[Reiji Watanabe]

On Thu, Jul 14, 2022 at 12:01 AM Marc Zyngier <maz@kernel.org> wrote:
>
> On Thu, 14 Jul 2022 07:37:25 +0100,
> Reiji Watanabe <reijiw@google.com> wrote:
> >
> > Hi Marc,
> >
> > On Wed, Jul 6, 2022 at 10:05 AM Marc Zyngier <maz@kernel.org> wrote:
> > >
> > > We carry a legacy interface to set the base addresses for GICv2.
> > > As this is currently plumbed into the same handling code as
> > > the modern interface, it limits the evolution we can make there.
> > >
> > > Add a helper dedicated to this handling, with a view of maybe
> > > removing this in the future.
> > >
> > > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > > ---
> > >  arch/arm64/kvm/arm.c                  | 11 ++-------
> > >  arch/arm64/kvm/vgic/vgic-kvm-device.c | 32 +++++++++++++++++++++++++++
> > >  include/kvm/arm_vgic.h                |  1 +
> > >  3 files changed, 35 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> > > index 83a7f61354d3..bf39570c0aef 100644
> > > --- a/arch/arm64/kvm/arm.c
> > > +++ b/arch/arm64/kvm/arm.c
> > > @@ -1414,18 +1414,11 @@ void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
> > >  static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
> > >                                         struct kvm_arm_device_addr *dev_addr)
> > >  {
> > > -       unsigned long dev_id, type;
> > > -
> > > -       dev_id = (dev_addr->id & KVM_ARM_DEVICE_ID_MASK) >>
> > > -               KVM_ARM_DEVICE_ID_SHIFT;
> > > -       type = (dev_addr->id & KVM_ARM_DEVICE_TYPE_MASK) >>
> > > -               KVM_ARM_DEVICE_TYPE_SHIFT;
> > > -
> > > -       switch (dev_id) {
> > > +       switch (FIELD_GET(KVM_ARM_DEVICE_ID_MASK, dev_addr->id)) {
> > >         case KVM_ARM_DEVICE_VGIC_V2:
> > >                 if (!vgic_present)
> > >                         return -ENXIO;
> > > -               return kvm_vgic_addr(kvm, type, &dev_addr->addr, true);
> > > +               return kvm_set_legacy_vgic_v2_addr(kvm, dev_addr);
> > >         default:
> > >                 return -ENODEV;
> > >         }
> > > diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > > index fbbd0338c782..0dfd277b9058 100644
> > > --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > > +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > > @@ -41,6 +41,38 @@ static int vgic_check_type(struct kvm *kvm, int type_needed)
> > >                 return 0;
> > >  }
> > >
> > > +int kvm_set_legacy_vgic_v2_addr(struct kvm *kvm, struct kvm_arm_device_addr *dev_addr)
> > > +{
> > > +       struct vgic_dist *vgic = &kvm->arch.vgic;
> > > +       int r;
> > > +
> > > +       mutex_lock(&kvm->lock);
> > > +       switch (FIELD_GET(KVM_ARM_DEVICE_ID_MASK, dev_addr->id)) {
> >
> > Shouldn't this be KVM_ARM_DEVICE_TYPE_MASK (not KVM_ARM_DEVICE_ID_MASK) ?
>
> Damn, you just ruined my attempt at deprecating this API ;-).

Oops, I should have pretended not to notice:)

> More seriously, thanks for catching this one!

Thank you for cleaning up the code so much!
Reiji

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[PATCH 16/19] KVM: arm64: vgic: Consolidate userspace access for base address setting

[Marc Zyngier]

Align kvm_vgic_addr() with the rest of the code by moving the
userspace accesses into it. kvm_vgic_addr() is also made static.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic/vgic-kvm-device.c | 70 ++++++++++++---------------
 include/kvm/arm_vgic.h                |  1 -
 2 files changed, 30 insertions(+), 41 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
index 0dfd277b9058..00ce7fca78dd 100644
--- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
+++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
@@ -76,8 +76,7 @@ int kvm_set_legacy_vgic_v2_addr(struct kvm *kvm, struct kvm_arm_device_addr *dev
 /**
  * kvm_vgic_addr - set or get vgic VM base addresses
  * @kvm:   pointer to the vm struct
- * @type:  the VGIC addr type, one of KVM_VGIC_V[23]_ADDR_TYPE_XXX
- * @addr:  pointer to address value
+ * @attr:  pointer to the attribute being retrieved/updated
  * @write: if true set the address in the VM address space, if false read the
  *          address
  *
@@ -89,15 +88,22 @@ int kvm_set_legacy_vgic_v2_addr(struct kvm *kvm, struct kvm_arm_device_addr *dev
  * overlapping regions in case of a virtual GICv3 here, since we don't know
  * the number of VCPUs yet, so we defer this check to map_resources().
  */
-int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
+static int kvm_vgic_addr(struct kvm *kvm, struct kvm_device_attr *attr, bool write)
 {
-	int r = 0;
+	u64 __user *uaddr = (u64 __user *)attr->addr;
 	struct vgic_dist *vgic = &kvm->arch.vgic;
 	phys_addr_t *addr_ptr, alignment, size;
 	u64 undef_value = VGIC_ADDR_UNDEF;
+	u64 addr;
+	int r;
+
+	/* Reading a redistributor region addr implies getting the index */
+	if (write || attr->attr == KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION)
+		if (get_user(addr, uaddr))
+			return -EFAULT;
 
 	mutex_lock(&kvm->lock);
-	switch (type) {
+	switch (attr->attr) {
 	case KVM_VGIC_V2_ADDR_TYPE_DIST:
 		r = vgic_check_type(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
 		addr_ptr = &vgic->vgic_dist_base;
@@ -123,7 +129,7 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
 		if (r)
 			break;
 		if (write) {
-			r = vgic_v3_set_redist_base(kvm, 0, *addr, 0);
+			r = vgic_v3_set_redist_base(kvm, 0, addr, 0);
 			goto out;
 		}
 		rdreg = list_first_entry_or_null(&vgic->rd_regions,
@@ -143,14 +149,12 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
 		if (r)
 			break;
 
-		index = *addr & KVM_VGIC_V3_RDIST_INDEX_MASK;
+		index = addr & KVM_VGIC_V3_RDIST_INDEX_MASK;
 
 		if (write) {
-			gpa_t base = *addr & KVM_VGIC_V3_RDIST_BASE_MASK;
-			u32 count = (*addr & KVM_VGIC_V3_RDIST_COUNT_MASK)
-					>> KVM_VGIC_V3_RDIST_COUNT_SHIFT;
-			u8 flags = (*addr & KVM_VGIC_V3_RDIST_FLAGS_MASK)
-					>> KVM_VGIC_V3_RDIST_FLAGS_SHIFT;
+			gpa_t base = addr & KVM_VGIC_V3_RDIST_BASE_MASK;
+			u32 count = FIELD_GET(KVM_VGIC_V3_RDIST_COUNT_MASK, addr);
+			u8 flags = FIELD_GET(KVM_VGIC_V3_RDIST_FLAGS_MASK, addr);
 
 			if (!count || flags)
 				r = -EINVAL;
@@ -166,9 +170,9 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
 			goto out;
 		}
 
-		*addr = index;
-		*addr |= rdreg->base;
-		*addr |= (u64)rdreg->count << KVM_VGIC_V3_RDIST_COUNT_SHIFT;
+		addr = index;
+		addr |= rdreg->base;
+		addr |= (u64)rdreg->count << KVM_VGIC_V3_RDIST_COUNT_SHIFT;
 		goto out;
 	}
 	default:
@@ -179,15 +183,20 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
 		goto out;
 
 	if (write) {
-		r = vgic_check_iorange(kvm, *addr_ptr, *addr, alignment, size);
+		r = vgic_check_iorange(kvm, *addr_ptr, addr, alignment, size);
 		if (!r)
-			*addr_ptr = *addr;
+			*addr_ptr = addr;
 	} else {
-		*addr = *addr_ptr;
+		addr = *addr_ptr;
 	}
 
 out:
 	mutex_unlock(&kvm->lock);
+
+	if (!r && !write)
+		if (put_user(addr, uaddr))
+			return -EFAULT;
+
 	return r;
 }
 
@@ -198,14 +207,7 @@ static int vgic_set_common_attr(struct kvm_device *dev,
 
 	switch (attr->group) {
 	case KVM_DEV_ARM_VGIC_GRP_ADDR: {
-		u64 __user *uaddr = (u64 __user *)(long)attr->addr;
-		u64 addr;
-		unsigned long type = (unsigned long)attr->attr;
-
-		if (get_user(addr, uaddr))
-			return -EFAULT;
-
-		r = kvm_vgic_addr(dev->kvm, type, &addr, true);
+		r = kvm_vgic_addr(dev->kvm, attr, true);
 		return (r == -ENODEV) ? -ENXIO : r;
 	}
 	case KVM_DEV_ARM_VGIC_GRP_NR_IRQS: {
@@ -261,20 +263,8 @@ static int vgic_get_common_attr(struct kvm_device *dev,
 
 	switch (attr->group) {
 	case KVM_DEV_ARM_VGIC_GRP_ADDR: {
-		u64 __user *uaddr = (u64 __user *)(long)attr->addr;
-		u64 addr;
-		unsigned long type = (unsigned long)attr->attr;
-
-		if (get_user(addr, uaddr))
-			return -EFAULT;
-
-		r = kvm_vgic_addr(dev->kvm, type, &addr, false);
-		if (r)
-			return (r == -ENODEV) ? -ENXIO : r;
-
-		if (put_user(addr, uaddr))
-			return -EFAULT;
-		break;
+		r = kvm_vgic_addr(dev->kvm, attr, false);
+		return (r == -ENODEV) ? -ENXIO : r;
 	}
 	case KVM_DEV_ARM_VGIC_GRP_NR_IRQS: {
 		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index f79cce67563e..4df9e73a8bb5 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -364,7 +364,6 @@ struct vgic_cpu {
 extern struct static_key_false vgic_v2_cpuif_trap;
 extern struct static_key_false vgic_v3_cpuif_trap;
 
-int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write);
 int kvm_set_legacy_vgic_v2_addr(struct kvm *kvm, struct kvm_arm_device_addr *dev_addr);
 void kvm_vgic_early_init(struct kvm *kvm);
 int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu);
-- 
2.34.1


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[PATCH 17/19] KVM: arm64: Get rid of find_reg_by_id()

[Marc Zyngier]

This helper doesn't have a user anymore, let's get rid of it.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 11 -----------
 arch/arm64/kvm/sys_regs.h |  5 -----
 2 files changed, 16 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index b66be9df7a02..d3ac0cd1c2e2 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2577,17 +2577,6 @@ static bool index_to_params(u64 id, struct sys_reg_params *params)
 	}
 }
 
-const struct sys_reg_desc *find_reg_by_id(u64 id,
-					  struct sys_reg_params *params,
-					  const struct sys_reg_desc table[],
-					  unsigned int num)
-{
-	if (!index_to_params(id, params))
-		return NULL;
-
-	return find_reg(params, table, num);
-}
-
 const struct sys_reg_desc *get_reg_by_id(u64 id,
 					 const struct sys_reg_desc table[],
 					 unsigned int num)
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index b8b576a2af2b..49517f58deb5 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -190,11 +190,6 @@ find_reg(const struct sys_reg_params *params, const struct sys_reg_desc table[],
 	return __inline_bsearch((void *)pval, table, num, sizeof(table[0]), match_sys_reg);
 }
 
-const struct sys_reg_desc *find_reg_by_id(u64 id,
-					  struct sys_reg_params *params,
-					  const struct sys_reg_desc table[],
-					  unsigned int num);
-
 const struct sys_reg_desc *get_reg_by_id(u64 id,
 					 const struct sys_reg_desc table[],
 					 unsigned int num);
-- 
2.34.1


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[PATCH 18/19] KVM: arm64: Descope kvm_arm_sys_reg_{get,set}_reg()

[Marc Zyngier]

Having kvm_arm_sys_reg_get_reg and co in kvm_host.h gives the
impression that these functions are free to be called from
anywhere.

Not quite. They really are tied to out internal sysreg handling,
and they would be better off in the sys_regs.h header, which is
private. kvm_host.h could also get a bit of a diet, so let's
just do that.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/kvm_host.h | 2 --
 arch/arm64/kvm/sys_regs.h         | 3 ++-
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index de32152cea04..0c9c85981a8e 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -620,8 +620,6 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
 
 unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu);
 int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices);
-int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
-int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
 
 int __kvm_arm_vcpu_get_events(struct kvm_vcpu *vcpu,
 			      struct kvm_vcpu_events *events);
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index 49517f58deb5..a8c4cc32eb9a 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -194,9 +194,10 @@ const struct sys_reg_desc *get_reg_by_id(u64 id,
 					 const struct sys_reg_desc table[],
 					 unsigned int num);
 
+int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
+int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
 int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
 			 const struct sys_reg_desc table[], unsigned int num);
-
 int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
 			 const struct sys_reg_desc table[], unsigned int num);
 
-- 
2.34.1


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[PATCH 19/19] KVM: arm64: Get rid or outdated comments

[Marc Zyngier]

Once apon a time, the 32bit KVM/arm port was the reference, while
the arm64 version was the new kid on the block, without a clear
future... This was a long time ago.

"The times, they are a-changing."

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index d3ac0cd1c2e2..8dc93d372d4f 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -34,11 +34,6 @@
 #include "trace.h"
 
 /*
- * All of this file is extremely similar to the ARM coproc.c, but the
- * types are different. My gut feeling is that it should be pretty
- * easy to merge, but that would be an ABI breakage -- again. VFP
- * would also need to be abstracted.
- *
  * For AArch32, we only take care of what is being trapped. Anything
  * that has to do with init and userspace access has to go via the
  * 64bit interface.
-- 
2.34.1


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