kvm/i386: implement architecture support for kvm file descriptor change
When the kvm file descriptor changes as a part of confidential guest reset, some architecture specific setups including SEV/SEV-SNP/TDX specific setups needs to be redone. These changes are implemented as a part of the kvm_arch_on_vmfd_change() callback which was introduced previously. Signed-off-by: Ani Sinha <anisinha@redhat.com> Link: https://lore.kernel.org/r/20260225035000.385950-11-anisinha@redhat.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ani Sinha committed
Feb 25, 2026 at 09:19 UTC
9d7e73222982c77a5eb36de149597b8be74d8011
2 files changed
+39
-11
target/i386/kvm/kvm.c
+38
-11
@@ -3407,12 +3407,30 @@ static int kvm_vm_enable_energy_msrs(KVMState *s)
3407
3408
int kvm_arch_on_vmfd_change(MachineState *ms, KVMState *s)
3409
{
3410
- abort();
3410
+ int ret;
3411
+
3412
+ ret = kvm_arch_init(ms, s);
3413
+ if (ret < 0) {
3414
+ return ret;
3415
+ }
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+
3417
+ if (object_dynamic_cast(OBJECT(ms), TYPE_X86_MACHINE)) {
3418
+ X86MachineState *x86ms = X86_MACHINE(ms);
3419
+
3420
+ if (x86_machine_is_smm_enabled(x86ms)) {
3421
+ memory_listener_register(&smram_listener.listener,
3422
+ &smram_address_space);
3423
+ }
3424
+ kvm_set_max_apic_id(x86ms->apic_id_limit);
3425
+ }
3426
+
3427
+ trace_kvm_arch_on_vmfd_change();
3428
+ return 0;
3429
}
3430
3431
bool kvm_arch_supports_vmfd_change(void)
3432
{
3415
- return false;
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+ return true;
3434
}
3435
3436
int kvm_arch_init(MachineState *ms, KVMState *s)
@@ -3420,6 +3438,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
3438
int ret;
3439
struct utsname utsname;
3440
Error *local_err = NULL;
3441
+ static bool first = true;
3442
3443
/*
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* Initialize confidential guest (SEV/TDX) context, if required
@@ -3489,16 +3508,17 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
3508
return ret;
3509
}
3510
3492
- /* Tell fw_cfg to notify the BIOS to reserve the range. */
3493
- e820_add_entry(KVM_IDENTITY_BASE, 0x4000, E820_RESERVED);
3494
-
3511
+ if (first) {
3512
+ /* Tell fw_cfg to notify the BIOS to reserve the range. */
3513
+ e820_add_entry(KVM_IDENTITY_BASE, 0x4000, E820_RESERVED);
3514
+ }
3515
ret = kvm_vm_set_nr_mmu_pages(s);
3516
if (ret < 0) {
3517
return ret;
3518
}
3519
3520
if (object_dynamic_cast(OBJECT(ms), TYPE_X86_MACHINE) &&
3501
- x86_machine_is_smm_enabled(X86_MACHINE(ms))) {
3521
+ x86_machine_is_smm_enabled(X86_MACHINE(ms)) && first) {
3522
smram_machine_done.notify = register_smram_listener;
3523
qemu_add_machine_init_done_notifier(&smram_machine_done);
3524
}
@@ -3545,16 +3565,23 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
3565
return ret;
3566
}
3567
3548
- ret = kvm_msr_energy_thread_init(s, ms);
3549
- if (ret < 0) {
3550
- error_report("kvm : error RAPL feature requirement not met");
3551
- return ret;
3568
+ if (first) {
3569
+ ret = kvm_msr_energy_thread_init(s, ms);
3570
+ if (ret < 0) {
3571
+ error_report("kvm : "
3572
+ "error RAPL feature requirement not met");
3573
+ return ret;
3574
+ }
3575
}
3576
}
3577
}
3578
3579
pmu_cap = kvm_check_extension(s, KVM_CAP_PMU_CAPABILITY);
3557
- kvm_vmfd_add_change_notifier(&kvm_vmfd_change_notifier);
3580
+
3581
+ if (first) {
3582
+ kvm_vmfd_add_change_notifier(&kvm_vmfd_change_notifier);
3583
+ }
3584
+ first = false;
3585
3586
return 0;
3587
}
target/i386/kvm/trace-events
+1
@@ -6,6 +6,7 @@ kvm_x86_add_msi_route(int virq) "Adding route entry for virq %d"
6
kvm_x86_remove_msi_route(int virq) "Removing route entry for virq %d"
7
kvm_x86_update_msi_routes(int num) "Updated %d MSI routes"
8
kvm_hc_map_gpa_range(uint64_t gpa, uint64_t size, uint64_t attributes, uint64_t flags) "gpa 0x%" PRIx64 " size 0x%" PRIx64 " attributes 0x%" PRIx64 " flags 0x%" PRIx64
9
+kvm_arch_on_vmfd_change(void) ""
10
11
# xen-emu.c
12
kvm_xen_hypercall(int cpu, uint8_t cpl, uint64_t input, uint64_t a0, uint64_t a1, uint64_t a2, uint64_t ret) "xen_hypercall: cpu %d cpl %d input %" PRIu64 " a0 0x%" PRIx64 " a1 0x%" PRIx64 " a2 0x%" PRIx64" ret 0x%" PRIx64