admin/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2025-12-07 20:06:24 +00:00
Code Issues Packages Projects Releases Wiki Activity

KVM: SVM: Expand AVIC_PHYSICAL_MAX_INDEX_MASK to be a 12-bit field

Browse Source 
In the latest APM describing AVIC support for 4k vCPUs, VMCB
AVIC_PHYSICAL_MAX_INDEX (Offset 0xF8) and EXITINFO2.Index are both
updated from 9-bit wide to 12-bit wide fields unconditionally (i.e.,
regardless of AVIC support for 4k vCPUs). Expand
AVIC_PHYSICAL_MAX_INDEX_MASK accordingly.

While AVIC_PHYSICAL_MAX_INDEX_MASK is updated to a 12-bit field, KVM
will limit the max vCPU/APIC ID based on the maximum supported on a
specific processor and enforce that limit during vCPU creation. I.e.,
KVM doesn't need to rely on the mask to ensure that the max APIC ID being
programmed in the VMCB is in range. The additional bits (11:9) were
previously marked reserved and were never set/read by older processors.

Signed-off-by: Naveen N Rao (AMD) <naveen@kernel.org>
Link: https://lore.kernel.org/r/a24ae953cea716bf9c56c136f7ca4bf5e97b1080.1757009416.git.naveen@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Naveen N Rao
2025-09-05 00:03:04 +05:30
committed by Sean Christopherson
parent 83f3cbcd3a
commit ca11d9d35e
1 changed files with 1 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/include/asm/svm.h
View File

@@ -279,7 +279,7 @@ enum avic_ipi_failure_cause {
AVIC_IPI_FAILURE_INVALID_IPI_VECTOR,
};
#define AVIC_PHYSICAL_MAX_INDEX_MASK GENMASK_ULL(8, 0)
#define AVIC_PHYSICAL_MAX_INDEX_MASK GENMASK_ULL(11, 0)
/*
* For AVIC, the max index allowed for physical APIC ID table is 0xfe (254), as