Re: [PATCH 19/26] KVM: arm64: Make struct kvm_regs userspace-only
On 2020-05-26 17:29, James Morse wrote:
Hi Marc,
On 22/04/2020 13:00, Marc Zyngier wrote:
struct kvm_regs is used by userspace to indicate which register gets
accessed by the {GET,SET}_ONE_REG API. But as we're about to refactor
the layout of the in-kernel register structures, we need the kernel to
move away from it.
Let's make kvm_regs userspace only, and let the kernel map it to its
own
internal representation.
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 23ebe51410f06..9fec9231b63e2 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -102,6 +102,55 @@ static int core_reg_size_from_offset(const struct
kvm_vcpu *vcpu, u64 off)
return size;
}
+static void *core_reg_addr(struct kvm_vcpu *vcpu, const struct
kvm_one_reg *reg)
+{
+ u64 off = core_reg_offset_from_id(reg->id);
+
+ switch (off) {
+ default:
+ return NULL;
Doesn't this switch statement catch an out of range offset, and a
misaligned offset?
... We still test for those explicitly in the caller. Better safe than
implicit?
Indeed, this is not supposed to happen at all. Maybe I should just fold
validate_core_offset offset there, and make this NULL value the error
case.
+ }
+}
With the reset thing reported by Zenghui and Zengtao on the previous
patch fixed:
Reviewed-by: James Morse
(otherwise struct kvm_regs isn't userspace-only!)
Indeed!
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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Re: [PATCH 19/26] KVM: arm64: Make struct kvm_regs userspace-only
Hi Marc,
On 22/04/2020 13:00, Marc Zyngier wrote:
> struct kvm_regs is used by userspace to indicate which register gets
> accessed by the {GET,SET}_ONE_REG API. But as we're about to refactor
> the layout of the in-kernel register structures, we need the kernel to
> move away from it.
>
> Let's make kvm_regs userspace only, and let the kernel map it to its own
> internal representation.
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index 23ebe51410f06..9fec9231b63e2 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -102,6 +102,55 @@ static int core_reg_size_from_offset(const struct
> kvm_vcpu *vcpu, u64 off)
> return size;
> }
>
> +static void *core_reg_addr(struct kvm_vcpu *vcpu, const struct kvm_one_reg
> *reg)
> +{
> + u64 off = core_reg_offset_from_id(reg->id);
> +
> + switch (off) {
> + default:
> + return NULL;
Doesn't this switch statement catch an out of range offset, and a misaligned
offset?
... We still test for those explicitly in the caller. Better safe than implicit?
> + }
> +}
With the reset thing reported by Zenghui and Zengtao on the previous patch
fixed:
Reviewed-by: James Morse
(otherwise struct kvm_regs isn't userspace-only!)
Thanks,
James
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