qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[PATCH v1 0/3] target/i386: Add the immediate form MSR access instructio


From: Xin Li (Intel)
Subject: [PATCH v1 0/3] target/i386: Add the immediate form MSR access instruction support
Date: Fri, 3 Jan 2025 00:48:24 -0800

The immediate form of MSR access instructions are primarily motivated by
performance, not code size: by having the MSR number in an immediate, it
is available *much* earlier in the pipeline, which allows the hardware
much more leeway about how a particular MSR is handled.

This new CPU feature is advertised through bit 5 of CPUID.7.1.ECX, which
needs to be added as a new CPU feature word.

WRMSRNS doesn't become a required feature for FERD, and Linux has removed
the dependency, as such remove the dependency from Qemu.


Xin Li (Intel) (3):
  target/i386: Remove FRED dependency on WRMSRNS
  target/i386: Add a new CPU feature word for CPUID.7.1.ECX
  target/i386: Add the immediate form MSR access instruction support

 target/i386/cpu.c | 27 ++++++++++++++++++++++-----
 target/i386/cpu.h |  4 ++++
 2 files changed, 26 insertions(+), 5 deletions(-)


base-commit: 1ada452efc7d8f8bf42cd5e8a2af1b4ac9167a1f
-- 
2.47.1




reply via email to

[Prev in Thread] Current Thread [Next in Thread]