On 12/05/2025 2:21 pm, Jan Beulich wrote:
> On 12.05.2025 13:58, Andrew Cooper wrote:
>> --- a/xen/arch/x86/include/asm/idt.h
>> +++ b/xen/arch/x86/include/asm/idt.h
>> @@ -92,15 +92,16 @@ static inline void _set_gate_lower(idt_entry_t *gate,
>> unsigned long type,
>> * Update the lower half handler of an IDT entry, without changing any other
>> * configuration.
>> */
>> -static inline void _update_gate_addr_lower(idt_entry_t *gate, void *addr)
>> +static inline void _update_gate_addr_lower(idt_entry_t *gate, void *_addr)
> Considering comment and name of the function, ...
>
>> {
>> + unsigned long addr = (unsigned long)_addr;
>> + unsigned int addr1 = addr & 0xffff0000U; /* GCC force better codegen. */
>> idt_entry_t idte;
>> - idte.a = gate->a;
>>
>> - idte.b = ((unsigned long)(addr) >> 32);
>> - idte.a &= 0x0000FFFFFFFF0000ULL;
>> - idte.a |= (((unsigned long)(addr) & 0xFFFF0000UL) << 32) |
>> - ((unsigned long)(addr) & 0xFFFFUL);
>> + idte.b = addr >> 32;
> ... doesn't this line want dropping altogether? Or at best be an assertion?
That's what _write_gate_lower() does, hence why
_update_gate_addr_lower() needs to calculate .b.
~Andrew
