Mostly i386 patches for QEMU 11.0 soft freeze

[PULL 037/102] target/arm/cpu64: Allow -host for nitro

Paolo Bonzini posted 102 patches 1 month, 1 week ago

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Maintainers: Paolo Bonzini <pbonzini@redhat.com>, Alexander Graf <graf@amazon.com>, Pedro Barbuda <pbarbuda@microsoft.com>, Mohamed Mediouni <mohamed@unpredictable.fr>, Gerd Hoffmann <kraxel@redhat.com>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Pierrick Bouvier <pierrick.bouvier@linaro.org>, Dorjoy Chowdhury <dorjoychy111@gmail.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>, "Michael S. Tsirkin" <mst@redhat.com>, Richard Henderson <richard.henderson@linaro.org>, Bernhard Beschow <shentey@gmail.com>, Alex Williamson <alex@shazbot.org>, "Cédric Le Goater" <clg@redhat.com>, Cornelia Huck <cohuck@redhat.com>, Peter Xu <peterx@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>, John Snow <jsnow@redhat.com>, Cleber Rosa <crosa@redhat.com>, Eric Blake <eblake@redhat.com>, Markus Armbruster <armbru@redhat.com>, Manos Pitsidianakis <manos.pitsidianakis@linaro.org>, "Alex Bennée" <alex.bennee@linaro.org>, Thomas Huth <thuth@redhat.com>, Ani Sinha <anisinha@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, Cameron Esfahani <dirty@apple.com>, Roman Bolshakov <rbolshakov@ddn.com>, Phil Dennis-Jordan <phil@philjordan.eu>, Wei Liu <wei.liu@kernel.org>, Marcelo Tosatti <mtosatti@redhat.com>, David Woodhouse <dwmw2@infradead.org>, Paul Durrant <paul@xen.org>, Magnus Kulke <magnus.kulke@linux.microsoft.com>, Fabiano Rosas <farosas@suse.de>, Laurent Vivier <lvivier@redhat.com>

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[PULL 037/102] target/arm/cpu64: Allow -host for nitro

Posted by Paolo Bonzini 1 month, 1 week ago

From: Alexander Graf <graf@amazon.com>

The nitro accel does not actually make use of CPU emulation or details:
It always uses the host CPU regardless of configuration. Machines for
the nitro accel select the host CPU type as default to have a clear
statement of the above and to have a unified cpu type across all
supported architectures.

The arm64 logic on Linux currently only allows -cpu host for KVM based
virtual machines. Add a special case for nitro so that when the nitro
accel is active, it allows use of the host cpu type.

Signed-off-by: Alexander Graf <graf@amazon.com>
Link: https://lore.kernel.org/r/20260225220807.33092-8-graf@amazon.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/arm/cpu64.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 58215216c55..d6feba220e8 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -813,6 +813,14 @@ static void aarch64_a53_initfn(Object *obj)
 static void aarch64_host_initfn(Object *obj)
 {
     ARMCPU *cpu = ARM_CPU(obj);
+
+#if defined(CONFIG_NITRO)
+    if (nitro_enabled()) {
+        /* The nitro accel uses -cpu host, but does not actually consume it */
+        return;
+    }
+#endif
+
 #if defined(CONFIG_KVM)
     kvm_arm_set_cpu_features_from_host(cpu);
     aarch64_add_sve_properties(obj);
-- 
2.53.0