[v1] Huge miscellaneous pull request for 2020-06-11

[PULL 035/115] hw/i386/vmport: Allow x2apic without IR

Paolo Bonzini posted 115 patches 5 years, 8 months ago

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Maintainers: Paolo Bonzini <pbonzini@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>, Colin Xu <colin.xu@intel.com>, "Michael S. Tsirkin" <mst@redhat.com>, Wenchao Wang <wenchao.wang@intel.com>, Peter Maydell <peter.maydell@linaro.org>, Alex Williamson <alex.williamson@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Fam Zheng <fam@euphon.net>, Igor Mammedov <imammedo@redhat.com>, Laurent Vivier <lvivier@redhat.com>, Marcelo Tosatti <mtosatti@redhat.com>, Roman Bolshakov <r.bolshakov@yadro.com>, Thomas Huth <thuth@redhat.com>, Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>, Richard Henderson <rth@twiddle.net>, Eduardo Habkost <ehabkost@redhat.com>, Hannes Reinecke <hare@suse.com>

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[PULL 035/115] hw/i386/vmport: Allow x2apic without IR

Posted by Paolo Bonzini 5 years, 8 months ago

From: Liran Alon <liran.alon@oracle.com>

Signal to guest that hypervisor supports x2apic without VT-d/IOMMU
Interrupt-Remapping support. This allows guest to use x2apic in
case all APIC IDs fits in 8-bit (i.e. Max APIC ID < 255).

See Linux kernel commit 4cca6ea04d31 ("x86/apic: Allow x2apic
without IR on VMware platform") and Linux try_to_enable_x2apic()
function.

Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Message-Id: <20200312165431.82118-14-liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/i386/vmport.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/hw/i386/vmport.c b/hw/i386/vmport.c
index 942a0e94e3..21d4ff048a 100644
--- a/hw/i386/vmport.c
+++ b/hw/i386/vmport.c
@@ -176,7 +176,14 @@ static uint32_t vmport_cmd_ram_size(void *opaque, uint32_t addr)
 
 static uint32_t vmport_cmd_get_vcpu_info(void *opaque, uint32_t addr)
 {
-    return 1 << VCPU_INFO_RESERVED_BIT;
+    X86CPU *cpu = X86_CPU(current_cpu);
+    uint32_t ret = 0;
+
+    if (cpu->env.features[FEAT_1_ECX] & CPUID_EXT_X2APIC) {
+        ret |= 1 << VCPU_INFO_LEGACY_X2APIC_BIT;
+    }
+
+    return ret;
 }
 
 static const MemoryRegionOps vmport_ops = {
-- 
2.26.2