Re: [PATCH v2 1/4] x86/xen: remove 32-bit Xen PV guest support

[Andrew Cooper]

On 02/07/2020 23:59, Boris Ostrovsky wrote:
> On 7/1/20 7:06 AM, Juergen Gross wrote:
>>  
>> -#ifdef CONFIG_X86_PAE
>> -static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
>> -{
>> -	trace_xen_mmu_set_pte_atomic(ptep, pte);
>> -	__xen_set_pte(ptep, pte);
>
> Probably not for this series but I wonder whether __xen_set_pte() should
> continue to use hypercall now that we are 64-bit only.

The hypercall path is a SYSCALL (and SYSRET out).

The "writeable" PTE path is a #PF, followed by an x86 instruction
emulation, which then reaches the same logic as the hypercall path (and
an IRET out).

~Andrew