On 08/11/17 10:13, Ingo Molnar wrote:
>
> * Juergen Gross <jgross@xxxxxxxx> wrote:
>
>> Add a new guest_late_init hook to the hypervisor_x86 structure. It
>> will replace the current kvm_guest_init() call which is changed to
>> make use of the new hook.
>>
>> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
>> ---
>> arch/x86/include/asm/hypervisor.h | 11 +++++++++++
>> arch/x86/include/asm/kvm_para.h | 2 --
>> arch/x86/kernel/kvm.c | 3 ++-
>> arch/x86/kernel/setup.c | 2 +-
>> 4 files changed, 14 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
>> index 0ead9dbb9130..37320687b8cb 100644
>> --- a/arch/x86/include/asm/hypervisor.h
>> +++ b/arch/x86/include/asm/hypervisor.h
>> @@ -38,6 +38,9 @@ struct hypervisor_x86 {
>> /* Platform setup (run once per boot) */
>> void (*init_platform)(void);
>>
>> + /* Guest late init */
>> + void (*guest_late_init)(void);
>> +
>> /* X2APIC detection (run once per boot) */
>> bool (*x2apic_available)(void);
>>
>> @@ -66,9 +69,17 @@ static inline void hypervisor_init_mem_mapping(void)
>> if (x86_hyper && x86_hyper->init_mem_mapping)
>> x86_hyper->init_mem_mapping();
>> }
>> +
>> +static inline void hypervisor_guest_late_init(void)
>> +{
>> + if (x86_hyper && x86_hyper->guest_late_init)
>> + x86_hyper->guest_late_init();
>> +}
>> +
>> #else
>> static inline void init_hypervisor_platform(void) { }
>> static inline bool hypervisor_x2apic_available(void) { return false; }
>> static inline void hypervisor_init_mem_mapping(void) { }
>> +static inline void hypervisor_guest_late_init(void) { }
>> #endif /* CONFIG_HYPERVISOR_GUEST */
>> #endif /* _ASM_X86_HYPERVISOR_H */
>> diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
>> index c373e44049b1..7b407dda2bd7 100644
>> --- a/arch/x86/include/asm/kvm_para.h
>> +++ b/arch/x86/include/asm/kvm_para.h
>> @@ -88,7 +88,6 @@ static inline long kvm_hypercall4(unsigned int nr, unsigned long p1,
>> #ifdef CONFIG_KVM_GUEST
>> bool kvm_para_available(void);
>> unsigned int kvm_arch_para_features(void);
>> -void __init kvm_guest_init(void);
>> void kvm_async_pf_task_wait(u32 token, int interrupt_kernel);
>> void kvm_async_pf_task_wake(u32 token);
>> u32 kvm_read_and_reset_pf_reason(void);
>> @@ -103,7 +102,6 @@ static inline void kvm_spinlock_init(void)
>> #endif /* CONFIG_PARAVIRT_SPINLOCKS */
>>
>> #else /* CONFIG_KVM_GUEST */
>> -#define kvm_guest_init() do {} while (0)
>> #define kvm_async_pf_task_wait(T, I) do {} while(0)
>> #define kvm_async_pf_task_wake(T) do {} while(0)
>>
>> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
>> index 8bb9594d0761..d331b5060aa9 100644
>> --- a/arch/x86/kernel/kvm.c
>> +++ b/arch/x86/kernel/kvm.c
>> @@ -465,7 +465,7 @@ static void __init kvm_apf_trap_init(void)
>> update_intr_gate(X86_TRAP_PF, async_page_fault);
>> }
>>
>> -void __init kvm_guest_init(void)
>> +static void __init kvm_guest_init(void)
>> {
>> int i;
>>
>> @@ -548,6 +548,7 @@ const struct hypervisor_x86 x86_hyper_kvm __refconst = {
>> .name = "KVM",
>> .detect = kvm_detect,
>> .x2apic_available = kvm_para_available,
>> + .guest_late_init = kvm_guest_init,
>> };
>> EXPORT_SYMBOL_GPL(x86_hyper_kvm);
>>
>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>> index 0957dd73d127..578569481d87 100644
>> --- a/arch/x86/kernel/setup.c
>> +++ b/arch/x86/kernel/setup.c
>> @@ -1294,7 +1294,7 @@ void __init setup_arch(char **cmdline_p)
>>
>> io_apic_init_mappings();
>>
>> - kvm_guest_init();
>> + hypervisor_guest_late_init();
>
> No principal objections, but could we please use a more obvious pattern showing
> that this is a callback, by calling it directly:
>
> x86_hyper->guest_late_init();
>
> Plus add a default empty function (which hypervisors can override). This avoids
> all the hidden conditions and wrappery.
Hmm, x86_hyper is just a pointer being NULL on bare metal. So we would
have to add a pre-filled struct with dummy functions and in case a
hypervisor is detected we'd need to copy all non-NULL pointers of the
hypervisor specific struct to the pre-filled one.
In case there are no objections I can add a patch to modify the current
way x86_hyper is used to the pre-filled variant.
Juergen
