Re: [PATCH v7 10/27] KVM: arm64: Propagate vcpu into read_id_reg()

[Andrew Jones]

On Fri, Mar 29, 2019 at 01:00:35PM +, Dave Martin wrote:
> Architecture features that are conditionally visible to the guest
> will require run-time checks in the ID register accessor functions.
> In particular, read_id_reg() will need to perform checks in order
> to generate the correct emulated value for certain ID register
> fields such as ID_AA64PFR0_EL1.SVE for example.
> 
> This patch propagates vcpu into read_id_reg() so that future
> patches can add run-time checks on the guest configuration here.
> 
> For now, there is no functional change.
> 
> Signed-off-by: Dave Martin 
> Reviewed-by: Alex Bennée 
> Tested-by: zhang.lei 
> ---
>  arch/arm64/kvm/sys_regs.c | 23 +--
>  1 file changed, 13 insertions(+), 10 deletions(-)
>

Reviewed-by: Andrew Jones 
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[PATCH v7 10/27] KVM: arm64: Propagate vcpu into read_id_reg()

[Dave Martin]

Architecture features that are conditionally visible to the guest
will require run-time checks in the ID register accessor functions.
In particular, read_id_reg() will need to perform checks in order
to generate the correct emulated value for certain ID register
fields such as ID_AA64PFR0_EL1.SVE for example.

This patch propagates vcpu into read_id_reg() so that future
patches can add run-time checks on the guest configuration here.

For now, there is no functional change.

Signed-off-by: Dave Martin 
Reviewed-by: Alex Bennée 
Tested-by: zhang.lei 
---
 arch/arm64/kvm/sys_regs.c | 23 +--
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 539feec..a5d14b5 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1044,7 +1044,8 @@ static bool access_arch_timer(struct kvm_vcpu *vcpu,
 }
 
 /* Read a sanitised cpufeature ID register by sys_reg_desc */
-static u64 read_id_reg(struct sys_reg_desc const *r, bool raz)
+static u64 read_id_reg(const struct kvm_vcpu *vcpu,
+   struct sys_reg_desc const *r, bool raz)
 {
u32 id = sys_reg((u32)r->Op0, (u32)r->Op1,
 (u32)r->CRn, (u32)r->CRm, (u32)r->Op2);
@@ -1078,7 +1079,7 @@ static bool __access_id_reg(struct kvm_vcpu *vcpu,
if (p->is_write)
return write_to_read_only(vcpu, p, r);
 
-   p->regval = read_id_reg(r, raz);
+   p->regval = read_id_reg(vcpu, r, raz);
return true;
 }
 
@@ -1107,16 +1108,18 @@ static u64 sys_reg_to_index(const struct sys_reg_desc 
*reg);
  * are stored, and for set_id_reg() we don't allow the effective value
  * to be changed.
  */
-static int __get_id_reg(const struct sys_reg_desc *rd, void __user *uaddr,
+static int __get_id_reg(const struct kvm_vcpu *vcpu,
+   const struct sys_reg_desc *rd, void __user *uaddr,
bool raz)
 {
const u64 id = sys_reg_to_index(rd);
-   const u64 val = read_id_reg(rd, raz);
+   const u64 val = read_id_reg(vcpu, rd, raz);
 
return reg_to_user(uaddr, &val, id);
 }
 
-static int __set_id_reg(const struct sys_reg_desc *rd, void __user *uaddr,
+static int __set_id_reg(const struct kvm_vcpu *vcpu,
+   const struct sys_reg_desc *rd, void __user *uaddr,
bool raz)
 {
const u64 id = sys_reg_to_index(rd);
@@ -1128,7 +1131,7 @@ static int __set_id_reg(const struct sys_reg_desc *rd, 
void __user *uaddr,
return err;
 
/* This is what we mean by invariant: you can't change it. */
-   if (val != read_id_reg(rd, raz))
+   if (val != read_id_reg(vcpu, rd, raz))
return -EINVAL;
 
return 0;
@@ -1137,25 +1140,25 @@ static int __set_id_reg(const struct sys_reg_desc *rd, 
void __user *uaddr,
 static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
  const struct kvm_one_reg *reg, void __user *uaddr)
 {
-   return __get_id_reg(rd, uaddr, false);
+   return __get_id_reg(vcpu, rd, uaddr, false);
 }
 
 static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
  const struct kvm_one_reg *reg, void __user *uaddr)
 {
-   return __set_id_reg(rd, uaddr, false);
+   return __set_id_reg(vcpu, rd, uaddr, false);
 }
 
 static int get_raz_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
  const struct kvm_one_reg *reg, void __user *uaddr)
 {
-   return __get_id_reg(rd, uaddr, true);
+   return __get_id_reg(vcpu, rd, uaddr, true);
 }
 
 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)
 {
-   return __set_id_reg(rd, uaddr, true);
+   return __set_id_reg(vcpu, rd, uaddr, true);
 }
 
 static bool access_ctr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
-- 
2.1.4

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