Re: [PATCH] KVM: x86: Account for 32-bit kernels when handling address in TSC attrs

[Paolo Bonzini]

On 11/10/21 16:35, Oliver Upton wrote:
> On Thu, Oct 7, 2021 at 6:16 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
> > When handling TSC attributes, cast the userspace provided virtual address
> > to an unsigned long before casting it to a pointer to fix warnings on
> > 32-bit kernels due to casting a 64-bit integer to a 32-bit pointer.
> >
> > Add a check that the truncated address matches the original address, e.g.
> > to prevent userspace specifying garbage in bits 63:32.
> >
> >    arch/x86/kvm/x86.c: In function ‘kvm_arch_tsc_get_attr’:
> >    arch/x86/kvm/x86.c:4947:22: error: cast to pointer from integer of different size
> >     4947 |  u64 __user *uaddr = (u64 __user *)attr->addr;
> >          |                      ^
> >    arch/x86/kvm/x86.c: In function ‘kvm_arch_tsc_set_attr’:
> >    arch/x86/kvm/x86.c:4967:22: error: cast to pointer from integer of different size
> >     4967 |  u64 __user *uaddr = (u64 __user *)attr->addr;
> >          |                      ^
> >
> > Cc: Oliver Upton <oupton@xxxxxxxxxx>
> > Fixes: 469fde25e680 ("KVM: x86: Expose TSC offset controls to userspace")
> > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> > ---
> >   arch/x86/kvm/x86.c | 10 ++++++++--
> >   1 file changed, 8 insertions(+), 2 deletions(-)
>
> Reviewed-by: Oliver Upton <oupton@xxxxxxxxxx>

Squashed, thanks.

Paolo