From 0a6e593487844fd00920c0caab64aa98eac368a1 Mon Sep 17 00:00:00 2001
From: Eduardo Habkost <ehabkost@redhat.com>
Date: Thu, 26 Jul 2018 17:19:04 +0100
Subject: [PATCH 14/14] i386: Allow TOPOEXT to be enabled on older kernels
RH-Author: Eduardo Habkost <ehabkost@redhat.com>
Message-id: <20180726171904.27418-12-ehabkost@redhat.com>
Patchwork-id: 81534
O-Subject: [qemu-kvm RHEL8/virt212 PATCH v2 11/11] i386: Allow TOPOEXT to be enabled on older kernels
Bugzilla: 1597739
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Igor Mammedov <imammedo@redhat.com>
From: Babu Moger <babu.moger@amd.com>
Enabling TOPOEXT feature might cause compatibility issues if
older kernels does not set this feature. Lets set this feature
unconditionally.
Signed-off-by: Babu Moger <babu.moger@amd.com>
Message-Id: <1528939107-17193-2-git-send-email-babu.moger@amd.com>
[ehabkost: rewrite comment and commit message]
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
(cherry picked from commit f98bbd8304112187cafc3e636c31b2a3865d2717)
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
target/i386/kvm.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 6e66f9c..bb5e485 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -371,6 +371,13 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function,
if (host_tsx_blacklisted()) {
ret &= ~(CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_HLE);
}
+ } else if (function == 0x80000001 && reg == R_ECX) {
+ /*
+ * It's safe to enable TOPOEXT even if it's not returned by
+ * GET_SUPPORTED_CPUID. Unconditionally enabling TOPOEXT here allows
+ * us to keep CPU models including TOPOEXT runnable on older kernels.
+ */
+ ret |= CPUID_EXT3_TOPOEXT;
} else if (function == 0x80000001 && reg == R_EDX) {
/* On Intel, kvm returns cpuid according to the Intel spec,
* so add missing bits according to the AMD spec:
--
1.8.3.1