diff options
| author | Jason Andryuk <jason.andryuk@amd.com> | 2025-04-10 22:31:05 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-04-11 12:39:50 +0300 |
| commit | 164a9f712fa53e4c92b2a435bb071a5be0c31dbc (patch) | |
| tree | ed4fdebaa39de8b026a155facb8a85def30fba62 | |
| parent | 0c7cae12f67c4c5fd232cffb27023deb409e1e20 (diff) | |
| download | linux-164a9f712fa53e4c92b2a435bb071a5be0c31dbc.tar.xz | |
x86/xen: Fix __xen_hypercall_setfunc()
Hypercall detection is failing with xen_hypercall_intel() chosen even on
an AMD processor. Looking at the disassembly, the call to
xen_get_vendor() was removed.
The check for boot_cpu_has(X86_FEATURE_CPUID) was used as a proxy for
the x86_vendor having been set.
When CONFIG_X86_REQUIRED_FEATURE_CPUID=y (the default value), DCE eliminates
the call to xen_get_vendor(). An uninitialized value 0 means
X86_VENDOR_INTEL, so the Intel function is always returned.
Remove the if and always call xen_get_vendor() to avoid this issue.
Fixes: 3d37d9396eb3 ("x86/cpufeatures: Add {REQUIRED,DISABLED} feature configs")
Suggested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Xin Li (Intel)" <xin@zytor.com>
Link: https://lore.kernel.org/r/20250410193106.16353-1-jason.andryuk@amd.com
| -rw-r--r-- | arch/x86/xen/enlighten.c | 7 |
1 files changed, 1 insertions, 6 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 1b7710bd0d05..53282dc7d5ac 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -103,10 +103,6 @@ noinstr void *__xen_hypercall_setfunc(void) void (*func)(void); /* - * Xen is supported only on CPUs with CPUID, so testing for - * X86_FEATURE_CPUID is a test for early_cpu_init() having been - * run. - * * Note that __xen_hypercall_setfunc() is noinstr only due to a nasty * dependency chain: it is being called via the xen_hypercall static * call when running as a PVH or HVM guest. Hypercalls need to be @@ -118,8 +114,7 @@ noinstr void *__xen_hypercall_setfunc(void) */ instrumentation_begin(); - if (!boot_cpu_has(X86_FEATURE_CPUID)) - xen_get_vendor(); + xen_get_vendor(); if ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD || boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)) |