On 18/08/2025 11:03 am, Jan Beulich wrote:
> On 08.08.2025 22:23, Andrew Cooper wrote:
>> diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
>> index 270b93ed623e..e67a428e4362 100644
>> --- a/xen/arch/x86/traps.c
>> +++ b/xen/arch/x86/traps.c
>> @@ -2181,6 +2240,94 @@ void asmlinkage check_ist_exit(const struct
>> cpu_user_regs *regs, bool ist_exit)
>> }
>> #endif
>>
>> +void asmlinkage entry_from_pv(struct cpu_user_regs *regs)
>> +{
>> + /* Copy fred_ss.vector into entry_vector as IDT delivery would have
>> done. */
>> + regs->entry_vector = regs->fred_ss.vector;
>> +
>> + switch ( regs->fred_ss.type )
>> + {
>> + case X86_ET_EXT_INTR:
>> + do_IRQ(regs);
>> + break;
>> +
>> + case X86_ET_NMI:
>> + do_nmi(regs);
>> + break;
>> +
>> + case X86_ET_HW_EXC:
>> + case X86_ET_SW_INT:
>> + case X86_ET_PRIV_SW_EXC:
>> + case X86_ET_SW_EXC:
>> + goto fatal;
>> +
>> + default:
>> + goto fatal;
>> + }
>> +
>> + return;
>> +
>> + fatal:
>> + fatal_trap(regs, false);
>> +}
> Noticed only now: Shouldn't this be surrounded with #ifdef CONFIG_PV (with
> knock-on effects elsewhere)?
Randconfig had a fun time with CONFIG_PV.
I've got an early "if ( IS_ENABLED(CONFIG_PV) ) goto fatal;" but there's
a bit of extra complexity in the ASM. entry_FRED_R3() needs to exist
even outside of CONFIG_PV, despite things like test_all_events being
conditional.
Also, this is changing a bit as part of getting PV support working.
~Andrew
