On 14/09/16 16:24, Jan Beulich wrote:
> No need to have the same logic twice.
>
> Signed-off-by: Jan Beulich <jbeul...@suse.com>
>
> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -1745,22 +1745,22 @@ static void load_segments(struct vcpu *n
> (unsigned long *)pv->kernel_sp;
> unsigned long cs_and_mask, rflags;
>
> + /* Fold upcall mask and architectural IOPL into RFLAGS.IF. */
> + rflags = regs->rflags & ~(X86_EFLAGS_IF|X86_EFLAGS_IOPL);
> + rflags |= !vcpu_info(n, evtchn_upcall_mask) << 9;
> + if ( VM_ASSIST(n->domain, architectural_iopl) )
> + rflags |= n->arch.pv_vcpu.iopl;
> +
> if ( is_pv_32bit_vcpu(n) )
> {
> unsigned int *esp = ring_1(regs) ?
> (unsigned int *)regs->rsp :
> (unsigned int *)pv->kernel_sp;
> - unsigned int cs_and_mask, eflags;
The unshadowed cs_and_mask is unsigned long, not int, which means the
put_user() below will clobber a 32bit PV guests stack frame.
Other than that, Reviewed-by: Andrew Cooper <andrew.coop...@citrix.com>
for the intended change.
~Andrew
> int ret = 0;
>
> /* CS longword also contains full evtchn_upcall_mask. */
> cs_and_mask = (unsigned short)regs->cs |
> ((unsigned int)vcpu_info(n, evtchn_upcall_mask) << 16);
> - /* Fold upcall mask into RFLAGS.IF. */
> - eflags = regs->_eflags & ~(X86_EFLAGS_IF|X86_EFLAGS_IOPL);
> - eflags |= !vcpu_info(n, evtchn_upcall_mask) << 9;
> - if ( VM_ASSIST(n->domain, architectural_iopl) )
> - eflags |= n->arch.pv_vcpu.iopl;
>
> if ( !ring_1(regs) )
> {
> @@ -1770,7 +1770,7 @@ static void load_segments(struct vcpu *n
> }
>
> if ( ret |
> - put_user(eflags, esp-1) |
> + put_user(rflags, esp-1) |
> put_user(cs_and_mask, esp-2) |
> put_user(regs->_eip, esp-3) |
> put_user(uregs->gs, esp-4) |
> @@ -1805,12 +1805,6 @@ static void load_segments(struct vcpu *n
> cs_and_mask = (unsigned long)regs->cs |
> ((unsigned long)vcpu_info(n, evtchn_upcall_mask) << 32);
>
> - /* Fold upcall mask into RFLAGS.IF. */
> - rflags = regs->rflags & ~(X86_EFLAGS_IF|X86_EFLAGS_IOPL);
> - rflags |= !vcpu_info(n, evtchn_upcall_mask) << 9;
> - if ( VM_ASSIST(n->domain, architectural_iopl) )
> - rflags |= n->arch.pv_vcpu.iopl;
> -
> if ( put_user(regs->ss, rsp- 1) |
> put_user(regs->rsp, rsp- 2) |
> put_user(rflags, rsp- 3) |
>
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> https://lists.xen.org/xen-devel
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
