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Commit 5c6183f3 authored by Maciej S. Szmigiero's avatar Maciej S. Szmigiero Committed by Greg Kroah-Hartman
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x86/CPU/AMD: Fix disabling XSAVES on AMD family 0x17 due to erratum 



The stable kernel version backport of the patch disabling XSAVES on AMD
Zen family 0x17 applied this change to the wrong function (init_amd_k6()),
one which isn't called for Zen CPUs.

Move the erratum to the init_amd_zn() function instead.

Add an explicit family 0x17 check to the erratum so nothing will break if
someone naively makes this kernel version call init_amd_zn() also for
family 0x19 in the future (as the current upstream code does).

Fixes: e40c1e9d ("x86/CPU/AMD: Disable XSAVES on AMD family 0x17")
Signed-off-by: default avatarMaciej S. Szmigiero <maciej.szmigiero@oracle.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7e180b70

arch/x86/kernel/cpu/amd.c

+11 −9
Original line number Diff line number Diff line
@@ -277,15 +277,6 @@ static void init_amd_k6(struct cpuinfo_x86 *c) 
		return;

	}

#endif

	/*

	 * Work around Erratum 1386.  The XSAVES instruction malfunctions in

	 * certain circumstances on Zen1/2 uarch, and not all parts have had

	 * updated microcode at the time of writing (March 2023).

	 *

	 * Affected parts all have no supervisor XSAVE states, meaning that

	 * the XSAVEC instruction (which works fine) is equivalent.

	 */

	clear_cpu_cap(c, X86_FEATURE_XSAVES);

}



static void init_amd_k7(struct cpuinfo_x86 *c)
@@ -989,6 +980,17 @@ static void init_amd_zn(struct cpuinfo_x86 *c) 
		if (c->x86 == 0x19 && !cpu_has(c, X86_FEATURE_BTC_NO))

			set_cpu_cap(c, X86_FEATURE_BTC_NO);

	}



	/*

	 * Work around Erratum 1386.  The XSAVES instruction malfunctions in

	 * certain circumstances on Zen1/2 uarch, and not all parts have had

	 * updated microcode at the time of writing (March 2023).

	 *

	 * Affected parts all have no supervisor XSAVE states, meaning that

	 * the XSAVEC instruction (which works fine) is equivalent.

	 */

	if (c->x86 == 0x17)

		clear_cpu_cap(c, X86_FEATURE_XSAVES);

}



static bool cpu_has_zenbleed_microcode(void)