diff options
Diffstat (limited to 'main/xen/xsa165.patch')
| -rw-r--r-- | main/xen/xsa165.patch | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/main/xen/xsa165.patch b/main/xen/xsa165.patch new file mode 100644 index 0000000000..81de03cd38 --- /dev/null +++ b/main/xen/xsa165.patch @@ -0,0 +1,85 @@ +x86: don't leak ST(n)/XMMn values to domains first using them + +FNINIT doesn't alter these registers, and hence using it is +insufficient to initialize a guest's initial state. + +This is XSA-165. + +Signed-off-by: Jan Beulich <jbeulich@suse.com> +Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com> + +--- a/xen/arch/x86/domain.c ++++ b/xen/arch/x86/domain.c +@@ -851,6 +851,17 @@ int arch_set_info_guest( + if ( v->arch.xsave_area ) + v->arch.xsave_area->xsave_hdr.xstate_bv = XSTATE_FP_SSE; + } ++ else if ( v->arch.xsave_area ) ++ memset(&v->arch.xsave_area->xsave_hdr, 0, ++ sizeof(v->arch.xsave_area->xsave_hdr)); ++ else ++ { ++ typeof(v->arch.xsave_area->fpu_sse) *fpu_sse = v->arch.fpu_ctxt; ++ ++ memset(fpu_sse, 0, sizeof(*fpu_sse)); ++ fpu_sse->fcw = FCW_DEFAULT; ++ fpu_sse->mxcsr = MXCSR_DEFAULT; ++ } + + if ( !compat ) + { +--- a/xen/arch/x86/i387.c ++++ b/xen/arch/x86/i387.c +@@ -17,19 +17,6 @@ + #include <asm/xstate.h> + #include <asm/asm_defns.h> + +-static void fpu_init(void) +-{ +- unsigned long val; +- +- asm volatile ( "fninit" ); +- if ( cpu_has_xmm ) +- { +- /* load default value into MXCSR control/status register */ +- val = MXCSR_DEFAULT; +- asm volatile ( "ldmxcsr %0" : : "m" (val) ); +- } +-} +- + /*******************************/ + /* FPU Restore Functions */ + /*******************************/ +@@ -248,15 +235,8 @@ void vcpu_restore_fpu_lazy(struct vcpu * + + if ( cpu_has_xsave ) + fpu_xrstor(v, XSTATE_LAZY); +- else if ( v->fpu_initialised ) +- { +- if ( cpu_has_fxsr ) +- fpu_fxrstor(v); +- else +- fpu_frstor(v); +- } + else +- fpu_init(); ++ fpu_fxrstor(v); + + v->fpu_initialised = 1; + v->fpu_dirtied = 1; +@@ -313,7 +293,14 @@ int vcpu_init_fpu(struct vcpu *v) + else + { + v->arch.fpu_ctxt = _xzalloc(sizeof(v->arch.xsave_area->fpu_sse), 16); +- if ( !v->arch.fpu_ctxt ) ++ if ( v->arch.fpu_ctxt ) ++ { ++ typeof(v->arch.xsave_area->fpu_sse) *fpu_sse = v->arch.fpu_ctxt; ++ ++ fpu_sse->fcw = FCW_DEFAULT; ++ fpu_sse->mxcsr = MXCSR_DEFAULT; ++ } ++ else + rc = -ENOMEM; + } + |