diff options
Diffstat (limited to '5ec2a760-x86-determine-MXCSR-mask-always.patch')
| -rw-r--r-- | 5ec2a760-x86-determine-MXCSR-mask-always.patch | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/5ec2a760-x86-determine-MXCSR-mask-always.patch b/5ec2a760-x86-determine-MXCSR-mask-always.patch new file mode 100644 index 0000000..9a5feb3 --- /dev/null +++ b/5ec2a760-x86-determine-MXCSR-mask-always.patch @@ -0,0 +1,69 @@ +# Commit 2b532519d64e653a6bbfd9eefed6040a09c8876d +# Date 2020-05-18 17:18:56 +0200 +# Author Jan Beulich <jbeulich@suse.com> +# Committer Jan Beulich <jbeulich@suse.com> +x86: determine MXCSR mask in all cases + +For its use(s) by the emulator to be correct in all cases, the filling +of the variable needs to be independent of XSAVE availability. As +there's no suitable function in i387.c to put the logic in, keep it in +xstate_init(), arrange for the function to be called unconditionally, +and pull the logic ahead of all return paths there. + +Fixes: 9a4496a35b20 ("x86emul: support {,V}{LD,ST}MXCSR") +Signed-off-by: Jan Beulich <jbeulich@suse.com> +Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com> + +--- a/xen/arch/x86/cpu/common.c ++++ b/xen/arch/x86/cpu/common.c +@@ -487,8 +487,7 @@ void identify_cpu(struct cpuinfo_x86 *c) + + /* Now the feature flags better reflect actual CPU features! */ + +- if ( cpu_has_xsave ) +- xstate_init(c); ++ xstate_init(c); + + #ifdef NOISY_CAPS + printk(KERN_DEBUG "CPU: After all inits, caps:"); +--- a/xen/arch/x86/xstate.c ++++ b/xen/arch/x86/xstate.c +@@ -587,6 +587,18 @@ void xstate_init(struct cpuinfo_x86 *c) + u32 eax, ebx, ecx, edx; + u64 feature_mask; + ++ if ( bsp ) ++ { ++ static typeof(current->arch.xsave_area->fpu_sse) __initdata ctxt; ++ ++ asm ( "fxsave %0" : "=m" (ctxt) ); ++ if ( ctxt.mxcsr_mask ) ++ mxcsr_mask = ctxt.mxcsr_mask; ++ } ++ ++ if ( !cpu_has_xsave ) ++ return; ++ + if ( (bsp && !use_xsave) || + boot_cpu_data.cpuid_level < XSTATE_CPUID ) + { +@@ -610,8 +622,6 @@ void xstate_init(struct cpuinfo_x86 *c) + + if ( bsp ) + { +- static typeof(current->arch.xsave_area->fpu_sse) __initdata ctxt; +- + xfeature_mask = feature_mask; + /* + * xsave_cntxt_size is the max size required by enabled features. +@@ -620,10 +630,6 @@ void xstate_init(struct cpuinfo_x86 *c) + xsave_cntxt_size = _xstate_ctxt_size(feature_mask); + printk("xstate: size: %#x and states: %#"PRIx64"\n", + xsave_cntxt_size, xfeature_mask); +- +- asm ( "fxsave %0" : "=m" (ctxt) ); +- if ( ctxt.mxcsr_mask ) +- mxcsr_mask = ctxt.mxcsr_mask; + } + else + { |