From: David Woodhouse <dwmw2@infradead.org>
To: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel <qemu-devel@nongnu.org>
Cc: x86 <x86@kernel.org>, kvm <kvm@vger.kernel.org>
Subject: [PATCH] x86/kvm: Reserve KVM_FEATURE_MSI_EXT_DEST_ID
Date: Mon, 19 Oct 2020 15:55:56 +0100 [thread overview]
Message-ID: <4cd59bed05f4b7410d3d1ffd1e997ab53683874d.camel@infradead.org> (raw)
In-Reply-To: <4d820db0-be0d-d47d-7a8a-874fb481a2ce@redhat.com>
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From: David Woodhouse <dwmw@amazon.co.uk>
No functional change; just reserve the feature bit for now so that VMMs
can start to implement it.
This will allow the host to indicate that MSI emulation supports 15-bit
destination IDs, allowing up to 32768 CPUs without interrupt remapping.
cf. https://patchwork.kernel.org/patch/11816693/ for qemu
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
---
Documentation/virt/kvm/cpuid.rst | 4 ++++
arch/x86/include/uapi/asm/kvm_para.h | 1 +
2 files changed, 5 insertions(+)
diff --git a/Documentation/virt/kvm/cpuid.rst b/Documentation/virt/kvm/cpuid.rst
index 9150e9d1c39b..f70b655821d5 100644
--- a/Documentation/virt/kvm/cpuid.rst
+++ b/Documentation/virt/kvm/cpuid.rst
@@ -92,6 +92,10 @@ KVM_FEATURE_ASYNC_PF_INT 14 guest checks this feature bit
async pf acknowledgment msr
0x4b564d07.
+KVM_FEATURE_MSI_EXT_DEST_ID 15 guest checks this feature bit
+ before using extended destination
+ ID bits in MSI address bits 11-5.
+
KVM_FEATURE_CLOCSOURCE_STABLE_BIT 24 host will warn if no guest-side
per-cpu warps are expeced in
kvmclock
diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
index 812e9b4c1114..950afebfba88 100644
--- a/arch/x86/include/uapi/asm/kvm_para.h
+++ b/arch/x86/include/uapi/asm/kvm_para.h
@@ -32,6 +32,7 @@
#define KVM_FEATURE_POLL_CONTROL 12
#define KVM_FEATURE_PV_SCHED_YIELD 13
#define KVM_FEATURE_ASYNC_PF_INT 14
+#define KVM_FEATURE_MSI_EXT_DEST_ID 15
#define KVM_HINTS_REALTIME 0
--
2.17.1
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prev parent reply other threads:[~2020-10-19 15:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-05 14:18 [PATCH] target/i386: Support up to 32768 CPUs without IRQ remapping David Woodhouse
2020-10-07 12:24 ` David Woodhouse
2020-10-08 6:56 ` Paolo Bonzini
2020-10-08 7:29 ` David Woodhouse
2020-10-08 7:53 ` Paolo Bonzini
2020-10-19 12:21 ` David Woodhouse
2020-10-19 13:55 ` Paolo Bonzini
2020-10-19 14:55 ` David Woodhouse [this message]
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