[PATCH v13 27/35] x86/traps: Add sysvec_install() to install a system interrupt handler

Xin Li
2023-12-05T11:23:03Z

Add sysvec_install() to install a system interrupt handler into the IDT
or the FRED system interrupt handler table.

Tested-by: Shan Kang <shan.kang@intel.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
---

Changes since v8:
* Introduce a macro sysvec_install() to derive the asm handler name from
a C handler, which simplifies the code and avoids an ugly typecast
(Thomas Gleixner).
---
arch/x86/entry/entry_fred.c | 14 ++++++++++++++
arch/x86/include/asm/desc.h | 2 --
arch/x86/include/asm/idtentry.h | 15 +++++++++++++++
arch/x86/kernel/cpu/acrn.c | 4 ++--
arch/x86/kernel/cpu/mshyperv.c | 15 +++++++--------
arch/x86/kernel/idt.c | 4 ++--
arch/x86/kernel/kvm.c | 2 +-
drivers/xen/events/events_base.c | 2 +-
8 files changed, 42 insertions(+), 16 deletions(-)

diff --git a/arch/x86/entry/entry_fred.c b/arch/x86/entry/entry_fred.c
index 215883e90f94..e80e3efbc057 100644
--- a/arch/x86/entry/entry_fred.c
+++ b/arch/x86/entry/entry_fred.c
@@ -126,6 +126,20 @@ static idtentry_t sysvec_table[NR_SYSTEM_VECTORS] __ro_after_init = {
SYSVEC(POSTED_INTR_NESTED_VECTOR, kvm_posted_intr_nested_ipi),
};

+static bool fred_setup_done __initdata;
+
+void __init fred_install_sysvec(unsigned int sysvec, idtentry_t handler)
+{
+ if (WARN_ON_ONCE(sysvec < FIRST_SYSTEM_VECTOR))
+ return;
+
+ if (WARN_ON_ONCE(fred_setup_done))
+ return;
+
+ if (!WARN_ON_ONCE(sysvec_table[sysvec - FIRST_SYSTEM_VECTOR]))
+ sysvec_table[sysvec - FIRST_SYSTEM_VECTOR] = handler;
+}
+
static noinstr void fred_extint(struct pt_regs *regs)
{
unsigned int vector = regs->fred_ss.vector;
diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index ab97b22ac04a..ec95fe44fa3a 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -402,8 +402,6 @@ static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit)
desc->limit1 = (limit >> 16) & 0xf;
}

-void alloc_intr_gate(unsigned int n, const void *addr);
-
static inline void init_idt_data(struct idt_data *data, unsigned int n,
const void *addr)
{
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 4f26ee9b8b74..650c98160152 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -459,6 +459,21 @@ __visible noinstr void func(struct pt_regs *regs, \
#define DEFINE_FREDENTRY_DEBUG DEFINE_FREDENTRY_RAW
#endif

+void idt_install_sysvec(unsigned int n, const void *function);
+
+#ifdef CONFIG_X86_FRED
+void fred_install_sysvec(unsigned int vector, const idtentry_t function);
+#else
+static inline void fred_install_sysvec(unsigned int vector, const idtentry_t function) { }
+#endif
+
+#define sysvec_install(vector, function) { \
+ if (cpu_feature_enabled(X86_FEATURE_FRED)) \
+ fred_install_sysvec(vector, function); \
+ else \
+ idt_install_sysvec(vector, asm_##function); \
+}
+
#else /* !__ASSEMBLY__ */

/*
diff --git a/arch/x86/kernel/cpu/acrn.c b/arch/x86/kernel/cpu/acrn.c
index bfeb18fad63f..2c5b51aad91a 100644
--- a/arch/x86/kernel/cpu/acrn.c
+++ b/arch/x86/kernel/cpu/acrn.c
@@ -26,8 +26,8 @@ static u32 __init acrn_detect(void)

static void __init acrn_init_platform(void)
{
- /* Setup the IDT for ACRN hypervisor callback */
- alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_acrn_hv_callback);
+ /* Install system interrupt handler for ACRN hypervisor callback */
+ sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_acrn_hv_callback);

x86_platform.calibrate_tsc = acrn_get_tsc_khz;
x86_platform.calibrate_cpu = acrn_get_tsc_khz;
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 01fa06dd06b6..45e0e70e238c 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -539,19 +539,18 @@ static void __init ms_hyperv_init_platform(void)
*/
x86_platform.apic_post_init = hyperv_init;
hyperv_setup_mmu_ops();
- /* Setup the IDT for hypervisor callback */
- alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_hyperv_callback);

- /* Setup the IDT for reenlightenment notifications */
+ /* Install system interrupt handler for hypervisor callback */
+ sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_hyperv_callback);
+
+ /* Install system interrupt handler for reenlightenment notifications */
if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) {
- alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,
- asm_sysvec_hyperv_reenlightenment);
+ sysvec_install(HYPERV_REENLIGHTENMENT_VECTOR, sysvec_hyperv_reenlightenment);
}

- /* Setup the IDT for stimer0 */
+ /* Install system interrupt handler for stimer0 */
if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) {
- alloc_intr_gate(HYPERV_STIMER0_VECTOR,
- asm_sysvec_hyperv_stimer0);
+ sysvec_install(HYPERV_STIMER0_VECTOR, sysvec_hyperv_stimer0);
}

# ifdef CONFIG_SMP
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 8857abc706e4..2b734927eec1 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -337,7 +337,7 @@ void idt_invalidate(void)
load_idt(&idt);
}

-void __init alloc_intr_gate(unsigned int n, const void *addr)
+void __init idt_install_sysvec(unsigned int n, const void *function)
{
if (WARN_ON(n < FIRST_SYSTEM_VECTOR))
return;
@@ -346,5 +346,5 @@ void __init alloc_intr_gate(unsigned int n, const void *addr)
return;

if (!WARN_ON(test_and_set_bit(n, system_vectors)))
- set_intr_gate(n, addr);
+ set_intr_gate(n, function);
}
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 0ddb3bd0f1aa..70d3aa717a29 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -829,7 +829,7 @@ static void __init kvm_guest_init(void)

if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) {
static_branch_enable(&kvm_async_pf_enabled);
- alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_kvm_asyncpf_interrupt);
+ sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_kvm_asyncpf_interrupt);
}

#ifdef CONFIG_SMP
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index b8cfea7812d6..e2813bac92d4 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -2216,7 +2216,7 @@ static __init void xen_alloc_callback_vector(void)
return;

pr_info("Xen HVM callback vector for event delivery is enabled\n");
- alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_xen_hvm_callback);
+ sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_xen_hvm_callback);
}
#else
void xen_setup_callback_vector(void) {}
--
2.43.0