The calls to xpti_init_default() in parse_xpti() are buggy. The CPUID data
hasn't been fetched that early, and boot_cpu_has(X86_FEATURE_ARCH_CAPS) will
always evaluate false.
As a result, the default case won't disable XPTI on Intel hardware which
advertises ARCH_CAPABILITIES_RDCL_NO.
Simplify parse_xpti() to solely the setting of opt_xpti according to the
passed string, and have init_speculation_mitigations() call
xpti_init_default() if appropiate. Drop the force parameter, and pass caps
instead, to avoid redundant re-reading of MSR_ARCH_CAPS.
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
---
CC: Jan Beulich <jbeul...@suse.com>
CC: Juergen Gross <jgr...@suse.com>
CC: Wei Liu <wei.l...@citrix.com>
CC: Roger Pau Monné <roger....@citrix.com>
CC: Sergey Dyasli <sergey.dya...@citrix.com>
---
xen/arch/x86/spec_ctrl.c | 17 +++++------------
1 file changed, 5 insertions(+), 12 deletions(-)
diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index 73dc717..32a4ea6 100644
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -423,17 +423,10 @@ static bool __init should_use_eager_fpu(void)
#define OPT_XPTI_DEFAULT 0xff
uint8_t __read_mostly opt_xpti = OPT_XPTI_DEFAULT;
-static __init void xpti_init_default(bool force)
+static __init void xpti_init_default(uint64_t caps)
{
- uint64_t caps = 0;
-
- if ( !force && (opt_xpti != OPT_XPTI_DEFAULT) )
- return;
-
if ( boot_cpu_data.x86_vendor == X86_VENDOR_AMD )
caps = ARCH_CAPABILITIES_RDCL_NO;
- else if ( boot_cpu_has(X86_FEATURE_ARCH_CAPS) )
- rdmsrl(MSR_ARCH_CAPABILITIES, caps);
if ( caps & ARCH_CAPABILITIES_RDCL_NO )
opt_xpti = 0;
@@ -446,8 +439,6 @@ static __init int parse_xpti(const char *s)
const char *ss;
int val, rc = 0;
- xpti_init_default(false);
-
do {
ss = strchr(s, ',');
if ( !ss )
@@ -465,7 +456,7 @@ static __init int parse_xpti(const char *s)
default:
if ( !strcmp(s, "default") )
- xpti_init_default(true);
+ opt_xpti = OPT_XPTI_DEFAULT;
else if ( (val = parse_boolean("dom0", s, ss)) >= 0 )
opt_xpti = (opt_xpti & ~OPT_XPTI_DOM0) |
(val ? OPT_XPTI_DOM0 : 0);
@@ -627,7 +618,9 @@ void __init init_speculation_mitigations(void)
if ( default_xen_spec_ctrl )
setup_force_cpu_cap(X86_FEATURE_SC_MSR_IDLE);
- xpti_init_default(false);
+ if ( opt_xpti == OPT_XPTI_DEFAULT )
+ xpti_init_default(caps);
+
if ( opt_xpti == 0 )
setup_force_cpu_cap(X86_FEATURE_NO_XPTI);
else
--
2.1.4
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