[tip: x86/cpu] x86/cpu/vfm: Add/initialize x86_vfm field to struct cpuinfo_x86

tip-bot2 for Tony Luck
2024-04-22T10:01:12Z

The following commit has been merged into the x86/cpu branch of tip:

Commit-ID: a9d0adce69075192961f3be466c4810a21b7bc9e
Gitweb: https://git.kernel.org/tip/a9d0adce69075192961f3be466c4810a21b7bc9e
Author: Tony Luck <tony.luck@intel.com>
AuthorDate: Tue, 16 Apr 2024 14:19:03 -07:00
Committer: Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Mon, 22 Apr 2024 11:43:48 +02:00

x86/cpu/vfm: Add/initialize x86_vfm field to struct cpuinfo_x86

Refactor struct cpuinfo_x86 so that the vendor, family, and model
fields are overlaid in a union with a 32-bit field that combines
all three (together with a one byte reserved field in the upper
byte).

This will make it easy, cheap, and reliable to check all three
values at once.

See

https://lore.kernel.org/r/Zgr6kT8oULbnmEXx@agluck-desk3

for why the ordering is (low-to-high bits):

(vendor, family, model)

[ bp: Move comments over the line, add the backstory about the
particular order of the fields. ]

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240416211941.9369-2-tony.luck@intel.com
---
arch/x86/include/asm/processor.h | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 811548f..e0f9251 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -108,9 +108,23 @@ struct cpuinfo_topology {
};

struct cpuinfo_x86 {
- __u8 x86; /* CPU family */
- __u8 x86_vendor; /* CPU vendor */
- __u8 x86_model;
+ union {
+ /*
+ * The particular ordering (low-to-high) of (vendor,
+ * family, model) is done in case range of models, like
+ * it is usually done on AMD, need to be compared.
+ */
+ struct {
+ __u8 x86_model;
+ /* CPU family */
+ __u8 x86;
+ /* CPU vendor */
+ __u8 x86_vendor;
+ __u8 x86_reserved;
+ };
+ /* combined vendor, family, model */
+ __u32 x86_vfm;
+ };
__u8 x86_stepping;
#ifdef CONFIG_X86_64
/* Number of 4K pages in DTLB/ITLB combined(in pages): */