From: Juergen Gross <jgross@suse.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Juergen Gross <jgross@suse.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
xen-devel@lists.xenproject.org,
Niels Dettenbach <nd@syndicat.com>
Subject: [PATCH] x86/xen: mark boot CPU of PV guest in MSR_IA32_APICBASE
Date: Mon, 7 Oct 2024 12:42:01 +0200 [thread overview]
Message-ID: <20241007104201.15607-1-jgross@suse.com> (raw)
Recent topology checks of the x86 boot code uncovered the need for
PV guests to have the boot cpu marked in the APICBASE MSR.
Fixes: 9d22c96316ac ("x86/topology: Handle bogus ACPI tables correctly")
Reported-by: Niels Dettenbach <nd@syndicat.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/xen/enlighten_pv.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 2c12ae42dc8b..d6818c6cafda 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1032,6 +1032,10 @@ static u64 xen_do_read_msr(unsigned int msr, int *err)
switch (msr) {
case MSR_IA32_APICBASE:
val &= ~X2APIC_ENABLE;
+ if (smp_processor_id() == 0)
+ val |= MSR_IA32_APICBASE_BSP;
+ else
+ val &= ~MSR_IA32_APICBASE_BSP;
break;
}
return val;
--
2.43.0
reply other threads:[~2024-10-07 10:42 UTC|newest]
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