From: David Woodhouse Date: Mon, 19 Oct 2020 15:55:56 +0100 Subject: x86/kvm: Reserve KVM_FEATURE_MSI_EXT_DEST_ID Git-commit: 5a169bf04cd2bfdbac967d12eb5b70915b29d7ee Patch-mainline: v5.10-rc2 References: bsc#1181001, jsc#ECO-3191 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 Acked-by: Paolo Bonzini Message-Id: <4cd59bed05f4b7410d3d1ffd1e997ab53683874d.camel@infradead.org> Signed-off-by: Paolo Bonzini Acked-by: Joerg Roedel --- Documentation/virtual/kvm/cpuid.txt | 4 ++++ arch/x86/include/uapi/asm/kvm_para.h | 1 + 2 files changed, 5 insertions(+) --- a/Documentation/virtual/kvm/cpuid.txt +++ b/Documentation/virtual/kvm/cpuid.txt @@ -58,6 +58,10 @@ KVM_FEATURE_ASYNC_PF_VMEXIT || || || can be enabled by setting bit 2 || || when writing to msr 0x4b564d02 ------------------------------------------------------------------------------ +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_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side || || per-cpu warps are expected in || || kvmclock. --- a/arch/x86/include/uapi/asm/kvm_para.h +++ b/arch/x86/include/uapi/asm/kvm_para.h @@ -24,6 +24,7 @@ #define KVM_FEATURE_PV_EOI 6 #define KVM_FEATURE_PV_UNHALT 7 #define KVM_FEATURE_ASYNC_PF_VMEXIT 10 +#define KVM_FEATURE_MSI_EXT_DEST_ID 15 /* The last 8 bits are used to indicate how to interpret the flags field * in pvclock structure. If no bits are set, all flags are ignored.