Introduce support for confidential guest reset (x86)

[PATCH v3 30/33] kvm/i386/apic: set local apic after vcpu file descriptors changed

Ani Sinha posted 33 patches 1 week, 6 days ago

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Maintainers: Paolo Bonzini <pbonzini@redhat.com>, Eduardo Habkost <eduardo@habkost.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Yanan Wang <wangyanan55@huawei.com>, Zhao Liu <zhao1.liu@intel.com>, "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>, Richard Henderson <richard.henderson@linaro.org>, "Michael S. Tsirkin" <mst@redhat.com>, David Woodhouse <dwmw2@infradead.org>, Paul Durrant <paul@xen.org>, Bernhard Beschow <shentey@gmail.com>, Alex Williamson <alex@shazbot.org>, "Cédric Le Goater" <clg@redhat.com>, Peter Xu <peterx@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, Marcelo Tosatti <mtosatti@redhat.com>, Song Gao <gaosong@loongson.cn>, Huacai Chen <chenhuacai@kernel.org>, Aurelien Jarno <aurelien@aurel32.net>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Aleksandar Rikalo <arikalo@gmail.com>, Nicholas Piggin <npiggin@gmail.com>, Harsh Prateek Bora <harshpb@linux.ibm.com>, Chinmay Rath <rathc@linux.ibm.com>, Palmer Dabbelt <palmer@dabbelt.com>, Alistair Francis <alistair.francis@wdc.com>, Weiwei Li <liwei1518@gmail.com>, Daniel Henrique Barboza <dbarboza@ventanamicro.com>, Liu Zhiwei <zhiwei_liu@linux.alibaba.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Eric Farman <farman@linux.ibm.com>, Matthew Rosato <mjrosato@linux.ibm.com>, Ilya Leoshkevich <iii@linux.ibm.com>, David Hildenbrand <david@kernel.org>, Thomas Huth <thuth@redhat.com>, Ani Sinha <anisinha@redhat.com>

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[PATCH v3 30/33] kvm/i386/apic: set local apic after vcpu file descriptors changed

Posted by Ani Sinha 1 week, 6 days ago

Once the vcpu file descriptors changed after confidential guest reset, the
local apic needs to be reinitialized. This change adds a callback from the
vcpu fd change notifiers to reinitialize local apic for kvm x86.

Signed-off-by: Ani Sinha <anisinha@redhat.com>
---
 hw/i386/kvm/apic.c              | 13 +++++++++++++
 include/hw/i386/apic_internal.h |  1 +
 2 files changed, 14 insertions(+)

diff --git a/hw/i386/kvm/apic.c b/hw/i386/kvm/apic.c
index 82355f0463..f6f8ac2764 100644
--- a/hw/i386/kvm/apic.c
+++ b/hw/i386/kvm/apic.c
@@ -229,6 +229,16 @@ static void kvm_apic_reset(APICCommonState *s)
     run_on_cpu(CPU(s->cpu), kvm_apic_put, RUN_ON_CPU_HOST_PTR(s));
 }
 
+static int apic_vcpufd_change_handler(NotifierWithReturn *n,
+                                      void *data, Error** errp) {
+    APICCommonState *s = container_of(n, APICCommonState,
+                                      vcpufd_change_notifier);
+
+    run_on_cpu(CPU(s->cpu), kvm_apic_put, RUN_ON_CPU_HOST_PTR(s));
+
+    return 0;
+}
+
 static void kvm_apic_realize(DeviceState *dev, Error **errp)
 {
     APICCommonState *s = APIC_COMMON(dev);
@@ -238,6 +248,9 @@ static void kvm_apic_realize(DeviceState *dev, Error **errp)
 
     assert(kvm_has_gsi_routing());
     msi_nonbroken = true;
+
+    s->vcpufd_change_notifier.notify = apic_vcpufd_change_handler;
+    kvm_vcpufd_add_change_notifier(&s->vcpufd_change_notifier);
 }
 
 static void kvm_apic_unrealize(DeviceState *dev)
diff --git a/include/hw/i386/apic_internal.h b/include/hw/i386/apic_internal.h
index 4a62fdceb4..ffe5815e7f 100644
--- a/include/hw/i386/apic_internal.h
+++ b/include/hw/i386/apic_internal.h
@@ -189,6 +189,7 @@ struct APICCommonState {
     hwaddr vapic_paddr; /* note: persistence via kvmvapic */
     bool legacy_instance_id;
     uint32_t extended_log_dest;
+    NotifierWithReturn vcpufd_change_notifier;
 };
 
 typedef struct VAPICState {
-- 
2.42.0

Re: [PATCH v3 30/33] kvm/i386/apic: set local apic after vcpu file descriptors changed

Posted by Ani Sinha 23 hours ago

On Tue, Jan 27, 2026 at 10:48 AM Ani Sinha <anisinha@redhat.com> wrote:
>
> Once the vcpu file descriptors changed after confidential guest reset, the
> local apic needs to be reinitialized. This change adds a callback from the
> vcpu fd change notifiers to reinitialize local apic for kvm x86.

This change is not necessary as kvm_apic_reset() does the same thing
as a part of the reset process. Will drop this patch in next spin up.

>
> Signed-off-by: Ani Sinha <anisinha@redhat.com>
> ---
>  hw/i386/kvm/apic.c              | 13 +++++++++++++
>  include/hw/i386/apic_internal.h |  1 +
>  2 files changed, 14 insertions(+)
>
> diff --git a/hw/i386/kvm/apic.c b/hw/i386/kvm/apic.c
> index 82355f0463..f6f8ac2764 100644
> --- a/hw/i386/kvm/apic.c
> +++ b/hw/i386/kvm/apic.c
> @@ -229,6 +229,16 @@ static void kvm_apic_reset(APICCommonState *s)
>      run_on_cpu(CPU(s->cpu), kvm_apic_put, RUN_ON_CPU_HOST_PTR(s));
>  }
>
> +static int apic_vcpufd_change_handler(NotifierWithReturn *n,
> +                                      void *data, Error** errp) {
> +    APICCommonState *s = container_of(n, APICCommonState,
> +                                      vcpufd_change_notifier);
> +
> +    run_on_cpu(CPU(s->cpu), kvm_apic_put, RUN_ON_CPU_HOST_PTR(s));
> +
> +    return 0;
> +}
> +
>  static void kvm_apic_realize(DeviceState *dev, Error **errp)
>  {
>      APICCommonState *s = APIC_COMMON(dev);
> @@ -238,6 +248,9 @@ static void kvm_apic_realize(DeviceState *dev, Error **errp)
>
>      assert(kvm_has_gsi_routing());
>      msi_nonbroken = true;
> +
> +    s->vcpufd_change_notifier.notify = apic_vcpufd_change_handler;
> +    kvm_vcpufd_add_change_notifier(&s->vcpufd_change_notifier);
>  }
>
>  static void kvm_apic_unrealize(DeviceState *dev)
> diff --git a/include/hw/i386/apic_internal.h b/include/hw/i386/apic_internal.h
> index 4a62fdceb4..ffe5815e7f 100644
> --- a/include/hw/i386/apic_internal.h
> +++ b/include/hw/i386/apic_internal.h
> @@ -189,6 +189,7 @@ struct APICCommonState {
>      hwaddr vapic_paddr; /* note: persistence via kvmvapic */
>      bool legacy_instance_id;
>      uint32_t extended_log_dest;
> +    NotifierWithReturn vcpufd_change_notifier;
>  };
>
>  typedef struct VAPICState {
> --
> 2.42.0
>