* [PATCH 1/5] KVM: x86: use static_call_cond for optional callbacks
2022-02-02 18:18 [PATCH 0/5] kvm: x86: better handling of NULL-able kvm_x86_ops Paolo Bonzini
@ 2022-02-02 18:18 ` Paolo Bonzini
2022-02-02 18:18 ` [PATCH 2/5] KVM: x86: mark NULL-able kvm_x86_ops Paolo Bonzini
` (4 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Paolo Bonzini @ 2022-02-02 18:18 UTC (permalink / raw)
To: linux-kernel, kvm; +Cc: seanjc
SVM implements neither update_emulated_instruction nor
set_apic_access_page_addr. Remove an "if" by calling them
with static_call_cond().
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/x86.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 862d654caedf..a527cffd0a2b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8421,8 +8421,7 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
kvm_rip_write(vcpu, ctxt->eip);
if (r && (ctxt->tf || (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)))
r = kvm_vcpu_do_singlestep(vcpu);
- if (kvm_x86_ops.update_emulated_instruction)
- static_call(kvm_x86_update_emulated_instruction)(vcpu);
+ static_call_cond(kvm_x86_update_emulated_instruction)(vcpu);
__kvm_set_rflags(vcpu, ctxt->eflags);
}
@@ -9838,10 +9837,7 @@ static void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
if (!lapic_in_kernel(vcpu))
return;
- if (!kvm_x86_ops.set_apic_access_page_addr)
- return;
-
- static_call(kvm_x86_set_apic_access_page_addr)(vcpu);
+ static_call_cond(kvm_x86_set_apic_access_page_addr)(vcpu);
}
void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu)
--
2.31.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH 2/5] KVM: x86: mark NULL-able kvm_x86_ops
2022-02-02 18:18 [PATCH 0/5] kvm: x86: better handling of NULL-able kvm_x86_ops Paolo Bonzini
2022-02-02 18:18 ` [PATCH 1/5] KVM: x86: use static_call_cond for optional callbacks Paolo Bonzini
@ 2022-02-02 18:18 ` Paolo Bonzini
2022-02-02 18:18 ` [PATCH 3/5] KVM: x86: warn on incorrectly NULL static calls Paolo Bonzini
` (3 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Paolo Bonzini @ 2022-02-02 18:18 UTC (permalink / raw)
To: linux-kernel, kvm; +Cc: seanjc
The original use of KVM_X86_OP_NULL, which was to mark calls
that do not follow a specific naming convention, is not in use
anymore. Repurpose it to identify calls that are invoked within
conditionals or with static_call_cond. Those that are _not_,
i.e. those that are defined with KVM_X86_OP, must be defined by
both vendor modules or some kind of NULL pointer dereference
is bound to happen at runtime.
In the case of apicv_post_status_restore, rather than changing
the kvm-x86-ops.h declaration, I decided to use static_call_cond;
there's no absolute requirement for vendor modules to support
APIC virtualization.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/include/asm/kvm-x86-ops.h | 30 ++++++++++++++----------------
arch/x86/kvm/lapic.c | 4 ++--
2 files changed, 16 insertions(+), 18 deletions(-)
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 9e37dc3d8863..a842f10f5778 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -6,16 +6,14 @@ BUILD_BUG_ON(1)
/*
* KVM_X86_OP() and KVM_X86_OP_NULL() are used to help generate
* "static_call()"s. They are also intended for use when defining
- * the vmx/svm kvm_x86_ops. KVM_X86_OP() can be used for those
- * functions that follow the [svm|vmx]_func_name convention.
- * KVM_X86_OP_NULL() can leave a NULL definition for the
- * case where there is no definition or a function name that
- * doesn't match the typical naming convention is supplied.
+ * the vmx/svm kvm_x86_ops. KVM_X86_OP_NULL() can be used for those
+ * functions that can have a NULL definition, for example if
+ * "static_call_cond()" will be used at the call sites.
*/
-KVM_X86_OP_NULL(hardware_enable)
-KVM_X86_OP_NULL(hardware_disable)
-KVM_X86_OP_NULL(hardware_unsetup)
-KVM_X86_OP_NULL(cpu_has_accelerated_tpr)
+KVM_X86_OP(hardware_enable)
+KVM_X86_OP(hardware_disable)
+KVM_X86_OP(hardware_unsetup)
+KVM_X86_OP(cpu_has_accelerated_tpr)
KVM_X86_OP(has_emulated_msr)
KVM_X86_OP(vcpu_after_set_cpuid)
KVM_X86_OP(vm_init)
@@ -33,7 +31,7 @@ KVM_X86_OP(get_segment_base)
KVM_X86_OP(get_segment)
KVM_X86_OP(get_cpl)
KVM_X86_OP(set_segment)
-KVM_X86_OP_NULL(get_cs_db_l_bits)
+KVM_X86_OP(get_cs_db_l_bits)
KVM_X86_OP(set_cr0)
KVM_X86_OP_NULL(post_set_cr3)
KVM_X86_OP(is_valid_cr4)
@@ -57,8 +55,8 @@ KVM_X86_OP(flush_tlb_gva)
KVM_X86_OP(flush_tlb_guest)
KVM_X86_OP(vcpu_pre_run)
KVM_X86_OP(vcpu_run)
-KVM_X86_OP_NULL(handle_exit)
-KVM_X86_OP_NULL(skip_emulated_instruction)
+KVM_X86_OP(handle_exit)
+KVM_X86_OP(skip_emulated_instruction)
KVM_X86_OP_NULL(update_emulated_instruction)
KVM_X86_OP(set_interrupt_shadow)
KVM_X86_OP(get_interrupt_shadow)
@@ -73,7 +71,7 @@ KVM_X86_OP(get_nmi_mask)
KVM_X86_OP(set_nmi_mask)
KVM_X86_OP(enable_nmi_window)
KVM_X86_OP(enable_irq_window)
-KVM_X86_OP(update_cr8_intercept)
+KVM_X86_OP_NULL(update_cr8_intercept)
KVM_X86_OP(check_apicv_inhibit_reasons)
KVM_X86_OP(refresh_apicv_exec_ctrl)
KVM_X86_OP(hwapic_irr_update)
@@ -88,7 +86,7 @@ KVM_X86_OP(set_tss_addr)
KVM_X86_OP(set_identity_map_addr)
KVM_X86_OP(get_mt_mask)
KVM_X86_OP(load_mmu_pgd)
-KVM_X86_OP_NULL(has_wbinvd_exit)
+KVM_X86_OP(has_wbinvd_exit)
KVM_X86_OP(get_l2_tsc_offset)
KVM_X86_OP(get_l2_tsc_multiplier)
KVM_X86_OP(write_tsc_offset)
@@ -96,7 +94,7 @@ KVM_X86_OP(write_tsc_multiplier)
KVM_X86_OP(get_exit_info)
KVM_X86_OP(check_intercept)
KVM_X86_OP(handle_exit_irqoff)
-KVM_X86_OP_NULL(request_immediate_exit)
+KVM_X86_OP(request_immediate_exit)
KVM_X86_OP(sched_in)
KVM_X86_OP_NULL(update_cpu_dirty_logging)
KVM_X86_OP_NULL(vcpu_blocking)
@@ -123,7 +121,7 @@ KVM_X86_OP(apic_init_signal_blocked)
KVM_X86_OP_NULL(enable_direct_tlbflush)
KVM_X86_OP_NULL(migrate_timers)
KVM_X86_OP(msr_filter_changed)
-KVM_X86_OP_NULL(complete_emulated_msr)
+KVM_X86_OP(complete_emulated_msr)
KVM_X86_OP(vcpu_deliver_sipi_vector)
#undef KVM_X86_OP
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 0da7d0960fcb..09bbb6a01c1d 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2369,7 +2369,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
vcpu->arch.pv_eoi.msr_val = 0;
apic_update_ppr(apic);
if (vcpu->arch.apicv_active) {
- static_call(kvm_x86_apicv_post_state_restore)(vcpu);
+ static_call_cond(kvm_x86_apicv_post_state_restore)(vcpu);
static_call(kvm_x86_hwapic_irr_update)(vcpu, -1);
static_call(kvm_x86_hwapic_isr_update)(vcpu, -1);
}
@@ -2634,7 +2634,7 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
kvm_apic_update_apicv(vcpu);
apic->highest_isr_cache = -1;
if (vcpu->arch.apicv_active) {
- static_call(kvm_x86_apicv_post_state_restore)(vcpu);
+ static_call_cond(kvm_x86_apicv_post_state_restore)(vcpu);
static_call(kvm_x86_hwapic_irr_update)(vcpu,
apic_find_highest_irr(apic));
static_call(kvm_x86_hwapic_isr_update)(vcpu,
--
2.31.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH 3/5] KVM: x86: warn on incorrectly NULL static calls
2022-02-02 18:18 [PATCH 0/5] kvm: x86: better handling of NULL-able kvm_x86_ops Paolo Bonzini
2022-02-02 18:18 ` [PATCH 1/5] KVM: x86: use static_call_cond for optional callbacks Paolo Bonzini
2022-02-02 18:18 ` [PATCH 2/5] KVM: x86: mark NULL-able kvm_x86_ops Paolo Bonzini
@ 2022-02-02 18:18 ` Paolo Bonzini
2022-02-02 18:18 ` [PATCH 4/5] KVM: x86: change hwapic_{irr,isr}_update to NULLable calls Paolo Bonzini
` (2 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Paolo Bonzini @ 2022-02-02 18:18 UTC (permalink / raw)
To: linux-kernel, kvm; +Cc: seanjc
Use the newly corrected KVM_X86_OP annotations to warn about possible
NULL pointer dereferences as soon as the vendor module is loaded.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/include/asm/kvm_host.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c371ee7e45f7..61faeb57889c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1544,9 +1544,10 @@ extern struct kvm_x86_ops kvm_x86_ops;
static inline void kvm_ops_static_call_update(void)
{
-#define KVM_X86_OP(func) \
+#define KVM_X86_OP_NULL(func) \
static_call_update(kvm_x86_##func, kvm_x86_ops.func);
-#define KVM_X86_OP_NULL KVM_X86_OP
+#define KVM_X86_OP(func) \
+ WARN_ON(!kvm_x86_ops.func); KVM_X86_OP_NULL(func)
#include <asm/kvm-x86-ops.h>
}
--
2.31.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH 4/5] KVM: x86: change hwapic_{irr,isr}_update to NULLable calls
2022-02-02 18:18 [PATCH 0/5] kvm: x86: better handling of NULL-able kvm_x86_ops Paolo Bonzini
` (2 preceding siblings ...)
2022-02-02 18:18 ` [PATCH 3/5] KVM: x86: warn on incorrectly NULL static calls Paolo Bonzini
@ 2022-02-02 18:18 ` Paolo Bonzini
2022-02-02 18:18 ` [PATCH 5/5] KVM: x86: allow defining return-0 static calls Paolo Bonzini
2022-02-08 0:41 ` [PATCH 0/5] kvm: x86: better handling of NULL-able kvm_x86_ops Sean Christopherson
5 siblings, 0 replies; 9+ messages in thread
From: Paolo Bonzini @ 2022-02-02 18:18 UTC (permalink / raw)
To: linux-kernel, kvm; +Cc: seanjc
SVM does not need them, so mark them as optional.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/include/asm/kvm-x86-ops.h | 4 ++--
arch/x86/kvm/lapic.c | 18 +++++++-----------
arch/x86/kvm/svm/avic.c | 8 --------
arch/x86/kvm/svm/svm.c | 2 --
4 files changed, 9 insertions(+), 23 deletions(-)
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index a842f10f5778..843bd9efd2ae 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -74,8 +74,8 @@ KVM_X86_OP(enable_irq_window)
KVM_X86_OP_NULL(update_cr8_intercept)
KVM_X86_OP(check_apicv_inhibit_reasons)
KVM_X86_OP(refresh_apicv_exec_ctrl)
-KVM_X86_OP(hwapic_irr_update)
-KVM_X86_OP(hwapic_isr_update)
+KVM_X86_OP_NULL(hwapic_irr_update)
+KVM_X86_OP_NULL(hwapic_isr_update)
KVM_X86_OP_NULL(guest_apic_has_interrupt)
KVM_X86_OP(load_eoi_exitmap)
KVM_X86_OP(set_virtual_apic_mode)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 09bbb6a01c1d..fd10dd070d26 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -492,8 +492,7 @@ static inline void apic_clear_irr(int vec, struct kvm_lapic *apic)
if (unlikely(vcpu->arch.apicv_active)) {
/* need to update RVI */
kvm_lapic_clear_vector(vec, apic->regs + APIC_IRR);
- static_call(kvm_x86_hwapic_irr_update)(vcpu,
- apic_find_highest_irr(apic));
+ static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, apic_find_highest_irr(apic));
} else {
apic->irr_pending = false;
kvm_lapic_clear_vector(vec, apic->regs + APIC_IRR);
@@ -523,7 +522,7 @@ static inline void apic_set_isr(int vec, struct kvm_lapic *apic)
* just set SVI.
*/
if (unlikely(vcpu->arch.apicv_active))
- static_call(kvm_x86_hwapic_isr_update)(vcpu, vec);
+ static_call_cond(kvm_x86_hwapic_isr_update)(vcpu, vec);
else {
++apic->isr_count;
BUG_ON(apic->isr_count > MAX_APIC_VECTOR);
@@ -571,8 +570,7 @@ static inline void apic_clear_isr(int vec, struct kvm_lapic *apic)
* and must be left alone.
*/
if (unlikely(vcpu->arch.apicv_active))
- static_call(kvm_x86_hwapic_isr_update)(vcpu,
- apic_find_highest_isr(apic));
+ static_call_cond(kvm_x86_hwapic_isr_update)(vcpu, apic_find_highest_isr(apic));
else {
--apic->isr_count;
BUG_ON(apic->isr_count < 0);
@@ -2370,8 +2368,8 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
apic_update_ppr(apic);
if (vcpu->arch.apicv_active) {
static_call_cond(kvm_x86_apicv_post_state_restore)(vcpu);
- static_call(kvm_x86_hwapic_irr_update)(vcpu, -1);
- static_call(kvm_x86_hwapic_isr_update)(vcpu, -1);
+ static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, -1);
+ static_call_cond(kvm_x86_hwapic_isr_update)(vcpu, -1);
}
vcpu->arch.apic_arb_prio = 0;
@@ -2635,10 +2633,8 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
apic->highest_isr_cache = -1;
if (vcpu->arch.apicv_active) {
static_call_cond(kvm_x86_apicv_post_state_restore)(vcpu);
- static_call(kvm_x86_hwapic_irr_update)(vcpu,
- apic_find_highest_irr(apic));
- static_call(kvm_x86_hwapic_isr_update)(vcpu,
- apic_find_highest_isr(apic));
+ static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, apic_find_highest_irr(apic));
+ static_call_cond(kvm_x86_hwapic_isr_update)(vcpu, apic_find_highest_isr(apic));
}
kvm_make_request(KVM_REQ_EVENT, vcpu);
if (ioapic_in_kernel(vcpu->kvm))
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 99f907ec5aa8..b49ee6f34fe7 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -592,14 +592,6 @@ void avic_set_virtual_apic_mode(struct kvm_vcpu *vcpu)
return;
}
-void avic_hwapic_irr_update(struct kvm_vcpu *vcpu, int max_irr)
-{
-}
-
-void avic_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr)
-{
-}
-
static int avic_set_pi_irte_mode(struct kvm_vcpu *vcpu, bool activate)
{
int ret = 0;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 7f70f456a5a5..ab50d73b1e2e 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4540,8 +4540,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
.refresh_apicv_exec_ctrl = avic_refresh_apicv_exec_ctrl,
.check_apicv_inhibit_reasons = avic_check_apicv_inhibit_reasons,
.load_eoi_exitmap = avic_load_eoi_exitmap,
- .hwapic_irr_update = avic_hwapic_irr_update,
- .hwapic_isr_update = avic_hwapic_isr_update,
.apicv_post_state_restore = avic_apicv_post_state_restore,
.set_tss_addr = svm_set_tss_addr,
--
2.31.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH 5/5] KVM: x86: allow defining return-0 static calls
2022-02-02 18:18 [PATCH 0/5] kvm: x86: better handling of NULL-able kvm_x86_ops Paolo Bonzini
` (3 preceding siblings ...)
2022-02-02 18:18 ` [PATCH 4/5] KVM: x86: change hwapic_{irr,isr}_update to NULLable calls Paolo Bonzini
@ 2022-02-02 18:18 ` Paolo Bonzini
2022-02-03 18:40 ` Paolo Bonzini
2022-02-08 0:41 ` [PATCH 0/5] kvm: x86: better handling of NULL-able kvm_x86_ops Sean Christopherson
5 siblings, 1 reply; 9+ messages in thread
From: Paolo Bonzini @ 2022-02-02 18:18 UTC (permalink / raw)
To: linux-kernel, kvm; +Cc: seanjc
A few vendor callbacks are only used by VMX, but they return an integer
or bool value. Introduce KVM_X86_OP_RET0 for them: a NULL value in
struct kvm_x86_ops will be changed to __static_call_return0.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/include/asm/kvm-x86-ops.h | 13 +++++++------
arch/x86/include/asm/kvm_host.h | 4 ++++
arch/x86/kvm/svm/avic.c | 5 -----
arch/x86/kvm/svm/svm.c | 26 --------------------------
arch/x86/kvm/x86.c | 2 +-
5 files changed, 12 insertions(+), 38 deletions(-)
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 843bd9efd2ae..89fa5dd21f34 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -13,7 +13,7 @@ BUILD_BUG_ON(1)
KVM_X86_OP(hardware_enable)
KVM_X86_OP(hardware_disable)
KVM_X86_OP(hardware_unsetup)
-KVM_X86_OP(cpu_has_accelerated_tpr)
+KVM_X86_OP_RET0(cpu_has_accelerated_tpr)
KVM_X86_OP(has_emulated_msr)
KVM_X86_OP(vcpu_after_set_cpuid)
KVM_X86_OP(vm_init)
@@ -76,15 +76,15 @@ KVM_X86_OP(check_apicv_inhibit_reasons)
KVM_X86_OP(refresh_apicv_exec_ctrl)
KVM_X86_OP_NULL(hwapic_irr_update)
KVM_X86_OP_NULL(hwapic_isr_update)
-KVM_X86_OP_NULL(guest_apic_has_interrupt)
+KVM_X86_OP_RET0(guest_apic_has_interrupt)
KVM_X86_OP(load_eoi_exitmap)
KVM_X86_OP(set_virtual_apic_mode)
KVM_X86_OP_NULL(set_apic_access_page_addr)
KVM_X86_OP(deliver_interrupt)
KVM_X86_OP_NULL(sync_pir_to_irr)
-KVM_X86_OP(set_tss_addr)
-KVM_X86_OP(set_identity_map_addr)
-KVM_X86_OP(get_mt_mask)
+KVM_X86_OP_RET0(set_tss_addr)
+KVM_X86_OP_RET0(set_identity_map_addr)
+KVM_X86_OP_RET0(get_mt_mask)
KVM_X86_OP(load_mmu_pgd)
KVM_X86_OP(has_wbinvd_exit)
KVM_X86_OP(get_l2_tsc_offset)
@@ -102,7 +102,7 @@ KVM_X86_OP_NULL(vcpu_unblocking)
KVM_X86_OP_NULL(pi_update_irte)
KVM_X86_OP_NULL(pi_start_assignment)
KVM_X86_OP_NULL(apicv_post_state_restore)
-KVM_X86_OP_NULL(dy_apicv_has_pending_interrupt)
+KVM_X86_OP_RET0(dy_apicv_has_pending_interrupt)
KVM_X86_OP_NULL(set_hv_timer)
KVM_X86_OP_NULL(cancel_hv_timer)
KVM_X86_OP(setup_mce)
@@ -126,3 +126,4 @@ KVM_X86_OP(vcpu_deliver_sipi_vector)
#undef KVM_X86_OP
#undef KVM_X86_OP_NULL
+#undef KVM_X86_OP_RET0
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 61faeb57889c..e7e5bd9a984d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1540,6 +1540,7 @@ extern struct kvm_x86_ops kvm_x86_ops;
#define KVM_X86_OP(func) \
DECLARE_STATIC_CALL(kvm_x86_##func, *(((struct kvm_x86_ops *)0)->func));
#define KVM_X86_OP_NULL KVM_X86_OP
+#define KVM_X86_OP_RET0 KVM_X86_OP
#include <asm/kvm-x86-ops.h>
static inline void kvm_ops_static_call_update(void)
@@ -1548,6 +1549,9 @@ static inline void kvm_ops_static_call_update(void)
static_call_update(kvm_x86_##func, kvm_x86_ops.func);
#define KVM_X86_OP(func) \
WARN_ON(!kvm_x86_ops.func); KVM_X86_OP_NULL(func)
+#define KVM_X86_OP_RET0(func) \
+ static_call_update(kvm_x86_##func, kvm_x86_ops.func ? : \
+ (typeof(kvm_x86_ops.func)) __static_call_return0);
#include <asm/kvm-x86-ops.h>
}
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index b49ee6f34fe7..c82457793fc8 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -707,11 +707,6 @@ int svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec)
return 0;
}
-bool avic_dy_apicv_has_pending_interrupt(struct kvm_vcpu *vcpu)
-{
- return false;
-}
-
static void svm_ir_list_del(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi)
{
unsigned long flags;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index ab50d73b1e2e..5f75f50b861c 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3479,16 +3479,6 @@ static void svm_enable_nmi_window(struct kvm_vcpu *vcpu)
svm->vmcb->save.rflags |= (X86_EFLAGS_TF | X86_EFLAGS_RF);
}
-static int svm_set_tss_addr(struct kvm *kvm, unsigned int addr)
-{
- return 0;
-}
-
-static int svm_set_identity_map_addr(struct kvm *kvm, u64 ident_addr)
-{
- return 0;
-}
-
static void svm_flush_tlb_current(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -3863,11 +3853,6 @@ static int __init svm_check_processor_compat(void)
return 0;
}
-static bool svm_cpu_has_accelerated_tpr(void)
-{
- return false;
-}
-
/*
* The kvm parameter can be NULL (module initialization, or invocation before
* VM creation). Be sure to check the kvm parameter before using it.
@@ -3890,11 +3875,6 @@ static bool svm_has_emulated_msr(struct kvm *kvm, u32 index)
return true;
}
-static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
-{
- return 0;
-}
-
static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -4470,7 +4450,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
.hardware_unsetup = svm_hardware_unsetup,
.hardware_enable = svm_hardware_enable,
.hardware_disable = svm_hardware_disable,
- .cpu_has_accelerated_tpr = svm_cpu_has_accelerated_tpr,
.has_emulated_msr = svm_has_emulated_msr,
.vcpu_create = svm_vcpu_create,
@@ -4542,10 +4521,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
.load_eoi_exitmap = avic_load_eoi_exitmap,
.apicv_post_state_restore = avic_apicv_post_state_restore,
- .set_tss_addr = svm_set_tss_addr,
- .set_identity_map_addr = svm_set_identity_map_addr,
- .get_mt_mask = svm_get_mt_mask,
-
.get_exit_info = svm_get_exit_info,
.vcpu_after_set_cpuid = svm_vcpu_after_set_cpuid,
@@ -4570,7 +4545,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
.nested_ops = &svm_nested_ops,
.deliver_interrupt = svm_deliver_interrupt,
- .dy_apicv_has_pending_interrupt = avic_dy_apicv_has_pending_interrupt,
.pi_update_irte = avic_pi_update_irte,
.setup_mce = svm_setup_mce,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a527cffd0a2b..2daca3dd128a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -129,6 +129,7 @@ struct kvm_x86_ops kvm_x86_ops __read_mostly;
DEFINE_STATIC_CALL_NULL(kvm_x86_##func, \
*(((struct kvm_x86_ops *)0)->func));
#define KVM_X86_OP_NULL KVM_X86_OP
+#define KVM_X86_OP_RET0 KVM_X86_OP
#include <asm/kvm-x86-ops.h>
EXPORT_STATIC_CALL_GPL(kvm_x86_get_cs_db_l_bits);
EXPORT_STATIC_CALL_GPL(kvm_x86_cache_reg);
@@ -12057,7 +12058,6 @@ void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
static inline bool kvm_guest_apic_has_interrupt(struct kvm_vcpu *vcpu)
{
return (is_guest_mode(vcpu) &&
- kvm_x86_ops.guest_apic_has_interrupt &&
static_call(kvm_x86_guest_apic_has_interrupt)(vcpu));
}
--
2.31.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH 5/5] KVM: x86: allow defining return-0 static calls
2022-02-02 18:18 ` [PATCH 5/5] KVM: x86: allow defining return-0 static calls Paolo Bonzini
@ 2022-02-03 18:40 ` Paolo Bonzini
2022-02-06 14:10 ` Peter Zijlstra
0 siblings, 1 reply; 9+ messages in thread
From: Paolo Bonzini @ 2022-02-03 18:40 UTC (permalink / raw)
To: linux-kernel, kvm; +Cc: seanjc, Peter Zijlstra
On 2/2/22 19:18, Paolo Bonzini wrote:
> A few vendor callbacks are only used by VMX, but they return an integer
> or bool value. Introduce KVM_X86_OP_RET0 for them: a NULL value in
> struct kvm_x86_ops will be changed to __static_call_return0.
This also needs EXPORT_SYMBOL_GPL(__static_call_ret0). Peter, any
objections?
Paolo
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> arch/x86/include/asm/kvm-x86-ops.h | 13 +++++++------
> arch/x86/include/asm/kvm_host.h | 4 ++++
> arch/x86/kvm/svm/avic.c | 5 -----
> arch/x86/kvm/svm/svm.c | 26 --------------------------
> arch/x86/kvm/x86.c | 2 +-
> 5 files changed, 12 insertions(+), 38 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
> index 843bd9efd2ae..89fa5dd21f34 100644
> --- a/arch/x86/include/asm/kvm-x86-ops.h
> +++ b/arch/x86/include/asm/kvm-x86-ops.h
> @@ -13,7 +13,7 @@ BUILD_BUG_ON(1)
> KVM_X86_OP(hardware_enable)
> KVM_X86_OP(hardware_disable)
> KVM_X86_OP(hardware_unsetup)
> -KVM_X86_OP(cpu_has_accelerated_tpr)
> +KVM_X86_OP_RET0(cpu_has_accelerated_tpr)
> KVM_X86_OP(has_emulated_msr)
> KVM_X86_OP(vcpu_after_set_cpuid)
> KVM_X86_OP(vm_init)
> @@ -76,15 +76,15 @@ KVM_X86_OP(check_apicv_inhibit_reasons)
> KVM_X86_OP(refresh_apicv_exec_ctrl)
> KVM_X86_OP_NULL(hwapic_irr_update)
> KVM_X86_OP_NULL(hwapic_isr_update)
> -KVM_X86_OP_NULL(guest_apic_has_interrupt)
> +KVM_X86_OP_RET0(guest_apic_has_interrupt)
> KVM_X86_OP(load_eoi_exitmap)
> KVM_X86_OP(set_virtual_apic_mode)
> KVM_X86_OP_NULL(set_apic_access_page_addr)
> KVM_X86_OP(deliver_interrupt)
> KVM_X86_OP_NULL(sync_pir_to_irr)
> -KVM_X86_OP(set_tss_addr)
> -KVM_X86_OP(set_identity_map_addr)
> -KVM_X86_OP(get_mt_mask)
> +KVM_X86_OP_RET0(set_tss_addr)
> +KVM_X86_OP_RET0(set_identity_map_addr)
> +KVM_X86_OP_RET0(get_mt_mask)
> KVM_X86_OP(load_mmu_pgd)
> KVM_X86_OP(has_wbinvd_exit)
> KVM_X86_OP(get_l2_tsc_offset)
> @@ -102,7 +102,7 @@ KVM_X86_OP_NULL(vcpu_unblocking)
> KVM_X86_OP_NULL(pi_update_irte)
> KVM_X86_OP_NULL(pi_start_assignment)
> KVM_X86_OP_NULL(apicv_post_state_restore)
> -KVM_X86_OP_NULL(dy_apicv_has_pending_interrupt)
> +KVM_X86_OP_RET0(dy_apicv_has_pending_interrupt)
> KVM_X86_OP_NULL(set_hv_timer)
> KVM_X86_OP_NULL(cancel_hv_timer)
> KVM_X86_OP(setup_mce)
> @@ -126,3 +126,4 @@ KVM_X86_OP(vcpu_deliver_sipi_vector)
>
> #undef KVM_X86_OP
> #undef KVM_X86_OP_NULL
> +#undef KVM_X86_OP_RET0
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 61faeb57889c..e7e5bd9a984d 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1540,6 +1540,7 @@ extern struct kvm_x86_ops kvm_x86_ops;
> #define KVM_X86_OP(func) \
> DECLARE_STATIC_CALL(kvm_x86_##func, *(((struct kvm_x86_ops *)0)->func));
> #define KVM_X86_OP_NULL KVM_X86_OP
> +#define KVM_X86_OP_RET0 KVM_X86_OP
> #include <asm/kvm-x86-ops.h>
>
> static inline void kvm_ops_static_call_update(void)
> @@ -1548,6 +1549,9 @@ static inline void kvm_ops_static_call_update(void)
> static_call_update(kvm_x86_##func, kvm_x86_ops.func);
> #define KVM_X86_OP(func) \
> WARN_ON(!kvm_x86_ops.func); KVM_X86_OP_NULL(func)
> +#define KVM_X86_OP_RET0(func) \
> + static_call_update(kvm_x86_##func, kvm_x86_ops.func ? : \
> + (typeof(kvm_x86_ops.func)) __static_call_return0);
> #include <asm/kvm-x86-ops.h>
> }
>
> diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
> index b49ee6f34fe7..c82457793fc8 100644
> --- a/arch/x86/kvm/svm/avic.c
> +++ b/arch/x86/kvm/svm/avic.c
> @@ -707,11 +707,6 @@ int svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec)
> return 0;
> }
>
> -bool avic_dy_apicv_has_pending_interrupt(struct kvm_vcpu *vcpu)
> -{
> - return false;
> -}
> -
> static void svm_ir_list_del(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi)
> {
> unsigned long flags;
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index ab50d73b1e2e..5f75f50b861c 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -3479,16 +3479,6 @@ static void svm_enable_nmi_window(struct kvm_vcpu *vcpu)
> svm->vmcb->save.rflags |= (X86_EFLAGS_TF | X86_EFLAGS_RF);
> }
>
> -static int svm_set_tss_addr(struct kvm *kvm, unsigned int addr)
> -{
> - return 0;
> -}
> -
> -static int svm_set_identity_map_addr(struct kvm *kvm, u64 ident_addr)
> -{
> - return 0;
> -}
> -
> static void svm_flush_tlb_current(struct kvm_vcpu *vcpu)
> {
> struct vcpu_svm *svm = to_svm(vcpu);
> @@ -3863,11 +3853,6 @@ static int __init svm_check_processor_compat(void)
> return 0;
> }
>
> -static bool svm_cpu_has_accelerated_tpr(void)
> -{
> - return false;
> -}
> -
> /*
> * The kvm parameter can be NULL (module initialization, or invocation before
> * VM creation). Be sure to check the kvm parameter before using it.
> @@ -3890,11 +3875,6 @@ static bool svm_has_emulated_msr(struct kvm *kvm, u32 index)
> return true;
> }
>
> -static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
> -{
> - return 0;
> -}
> -
> static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
> {
> struct vcpu_svm *svm = to_svm(vcpu);
> @@ -4470,7 +4450,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
> .hardware_unsetup = svm_hardware_unsetup,
> .hardware_enable = svm_hardware_enable,
> .hardware_disable = svm_hardware_disable,
> - .cpu_has_accelerated_tpr = svm_cpu_has_accelerated_tpr,
> .has_emulated_msr = svm_has_emulated_msr,
>
> .vcpu_create = svm_vcpu_create,
> @@ -4542,10 +4521,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
> .load_eoi_exitmap = avic_load_eoi_exitmap,
> .apicv_post_state_restore = avic_apicv_post_state_restore,
>
> - .set_tss_addr = svm_set_tss_addr,
> - .set_identity_map_addr = svm_set_identity_map_addr,
> - .get_mt_mask = svm_get_mt_mask,
> -
> .get_exit_info = svm_get_exit_info,
>
> .vcpu_after_set_cpuid = svm_vcpu_after_set_cpuid,
> @@ -4570,7 +4545,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
> .nested_ops = &svm_nested_ops,
>
> .deliver_interrupt = svm_deliver_interrupt,
> - .dy_apicv_has_pending_interrupt = avic_dy_apicv_has_pending_interrupt,
> .pi_update_irte = avic_pi_update_irte,
> .setup_mce = svm_setup_mce,
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index a527cffd0a2b..2daca3dd128a 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -129,6 +129,7 @@ struct kvm_x86_ops kvm_x86_ops __read_mostly;
> DEFINE_STATIC_CALL_NULL(kvm_x86_##func, \
> *(((struct kvm_x86_ops *)0)->func));
> #define KVM_X86_OP_NULL KVM_X86_OP
> +#define KVM_X86_OP_RET0 KVM_X86_OP
> #include <asm/kvm-x86-ops.h>
> EXPORT_STATIC_CALL_GPL(kvm_x86_get_cs_db_l_bits);
> EXPORT_STATIC_CALL_GPL(kvm_x86_cache_reg);
> @@ -12057,7 +12058,6 @@ void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
> static inline bool kvm_guest_apic_has_interrupt(struct kvm_vcpu *vcpu)
> {
> return (is_guest_mode(vcpu) &&
> - kvm_x86_ops.guest_apic_has_interrupt &&
> static_call(kvm_x86_guest_apic_has_interrupt)(vcpu));
> }
>
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH 5/5] KVM: x86: allow defining return-0 static calls
2022-02-03 18:40 ` Paolo Bonzini
@ 2022-02-06 14:10 ` Peter Zijlstra
0 siblings, 0 replies; 9+ messages in thread
From: Peter Zijlstra @ 2022-02-06 14:10 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: linux-kernel, kvm, seanjc
On Thu, Feb 03, 2022 at 07:40:25PM +0100, Paolo Bonzini wrote:
> On 2/2/22 19:18, Paolo Bonzini wrote:
> > A few vendor callbacks are only used by VMX, but they return an integer
> > or bool value. Introduce KVM_X86_OP_RET0 for them: a NULL value in
> > struct kvm_x86_ops will be changed to __static_call_return0.
>
> This also needs EXPORT_SYMBOL_GPL(__static_call_ret0). Peter, any
> objections?
__static_call_return0 I suppose, but no. Go ahead.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 0/5] kvm: x86: better handling of NULL-able kvm_x86_ops
2022-02-02 18:18 [PATCH 0/5] kvm: x86: better handling of NULL-able kvm_x86_ops Paolo Bonzini
` (4 preceding siblings ...)
2022-02-02 18:18 ` [PATCH 5/5] KVM: x86: allow defining return-0 static calls Paolo Bonzini
@ 2022-02-08 0:41 ` Sean Christopherson
5 siblings, 0 replies; 9+ messages in thread
From: Sean Christopherson @ 2022-02-08 0:41 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: linux-kernel, kvm
On Wed, Feb 02, 2022, Paolo Bonzini wrote:
> This series is really two changes:
>
> - patch 1 to 4 clean up NULLable kvm_x86_ops so that they are marked
> in kvm-x86-ops.h and the non-NULLable ones WARN if used incorrectly.
> As an additional outcome of the review, a few more uses of
> static_call_cond are introduced.
>
> - patch 5 allows to NULL a few kvm_x86_ops that return a value, by
> using __static_call_ret0.
>
> Paolo Bonzini (5):
> KVM: x86: use static_call_cond for optional callbacks
> KVM: x86: mark NULL-able kvm_x86_ops
> KVM: x86: warn on incorrectly NULL static calls
> KVM: x86: change hwapic_{irr,isr}_update to NULLable calls
> KVM: x86: allow defining return-0 static calls
I belatedly remembered the other thing about "NULL" that I don't like:
#define KVM_X86_OP(func) \
DEFINE_STATIC_CALL_NULL(kvm_x86_##func, \
*(((struct kvm_x86_ops *)0)->func));
#define KVM_X86_OP_NULL KVM_X86_OP
That's bound to be confusing for folks that aren't already familiar with the
code, especially if they don't have a good handle on static_call() magic.
Side topic, the above doesn't handle KVM_X86_OP_RET0, no idea how that doesn't
fail at link time. The BUILD_BUG_ON(1) in kvm-x86-ops.h also needs to be updated,
and the comment too.
Anyways, back to NULL. KVM_X86_OP_RET0 also doesn't capture that the hook can
be NULL in that case; if the reader is familiar with static_call() then they'll
understand the full meaning, but I doubt that covers the majority of readers.
TL;DR: what about using more verbose names KVM_X86_OP_OPTIONAL and
KVM_X86_OP_OPTIONAL_RET0[*]? And also tweak kvm_ops_static_call_update()'s
defines so that KVM_X86_OP never routes through KVM_X86_OP_OPTIONAL (as syntactic
sugar to avoid confusion.
Other than that, I like the WARN on KVM_X86_OPS with a NULL implementation.
[*] The OP_OPTIONAL kills me, but I can't think of a better alternative.
E.g. sans the kvm-x86-ops.h changes...
---
arch/x86/include/asm/kvm_host.h | 11 ++++++-----
arch/x86/kvm/x86.c | 11 +++++++++--
2 files changed, 15 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index e7e5bd9a984d..055b3a2419f7 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1539,17 +1539,18 @@ extern struct kvm_x86_ops kvm_x86_ops;
#define KVM_X86_OP(func) \
DECLARE_STATIC_CALL(kvm_x86_##func, *(((struct kvm_x86_ops *)0)->func));
-#define KVM_X86_OP_NULL KVM_X86_OP
-#define KVM_X86_OP_RET0 KVM_X86_OP
+#define KVM_X86_OP_OPTIONAL KVM_X86_OP
+#define KVM_X86_OP_OPTIONAL_RET0 KVM_X86_OP
#include <asm/kvm-x86-ops.h>
static inline void kvm_ops_static_call_update(void)
{
-#define KVM_X86_OP_NULL(func) \
+#define __KVM_X86_OP(func) \
static_call_update(kvm_x86_##func, kvm_x86_ops.func);
#define KVM_X86_OP(func) \
- WARN_ON(!kvm_x86_ops.func); KVM_X86_OP_NULL(func)
-#define KVM_X86_OP_RET0(func) \
+ WARN_ON(!kvm_x86_ops.func); __KVM_X86_OP(func)
+#define KVM_X86_OP_OPTIONAL __KVM_X86_OP
+#define KVM_X86_OP_OPTIONAL_RET0(func) \
static_call_update(kvm_x86_##func, kvm_x86_ops.func ? : \
(typeof(kvm_x86_ops.func)) __static_call_return0);
#include <asm/kvm-x86-ops.h>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 657aa646871e..337e39dec3c4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -125,11 +125,18 @@ static void __get_sregs2(struct kvm_vcpu *vcpu, struct kvm_sregs2 *sregs2);
struct kvm_x86_ops kvm_x86_ops __read_mostly;
+/*
+ * All ops are filled by vendor code, thus the default function is NULL for
+ * both mandatory and optional hooks. The exception are optional RET0 hooks,
+ * which obviously default to __static_call_return0.
+ */
#define KVM_X86_OP(func) \
DEFINE_STATIC_CALL_NULL(kvm_x86_##func, \
*(((struct kvm_x86_ops *)0)->func));
-#define KVM_X86_OP_NULL KVM_X86_OP
-#define KVM_X86_OP_RET0 KVM_X86_OP
+#define KVM_X86_OP_OPTIONAL KVM_X86_OP
+#define KVM_X86_OP_OPTIONAL_RET0(func) \
+ DEFINE_STATIC_CALL_RET0(kvm_x86_##func, \
+ *(((struct kvm_x86_ops *)0)->func));
#include <asm/kvm-x86-ops.h>
EXPORT_STATIC_CALL_GPL(kvm_x86_get_cs_db_l_bits);
EXPORT_STATIC_CALL_GPL(kvm_x86_cache_reg);
base-commit: 347f6a965596211726c39eb6bc320e8375f80b52
--
^ permalink raw reply related [flat|nested] 9+ messages in thread