fpu.state is allocated from task_xstate_cachep, the size of task_xstate_cachep is xstate_size. xstate_size is set from cpuid instruction, which is often smaller than sizeof(struct xsave_struct). kvm is using sizeof(struct xsave_struct) to fill in/out fpu.state.xsave, as what we allocated for fpu.state is xstate_size, kernel will write out of memory and caused poison/redzone/padding overwritten warnings.
Signed-off-by: Xiaotian Feng <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Suresh Siddha <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Avi Kivity <[email protected]> Cc: Robert Richter <[email protected]> Cc: Sheng Yang <[email protected]> Cc: Marcelo Tosatti <[email protected]> Cc: Gleb Natapov <[email protected]> Cc: Jan Kiszka <[email protected]> --- arch/x86/kernel/i387.c | 1 + arch/x86/kvm/x86.c | 4 ++-- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 1f11f5c..a46cb35 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -40,6 +40,7 @@ static unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu; unsigned int xstate_size; +EXPORT_SYMBOL_GPL(xstate_size); unsigned int sig_xstate_ia32_size = sizeof(struct _fpstate_ia32); static struct i387_fxsave_struct fx_scratch __cpuinitdata; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 25f1907..3a09c62 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2387,7 +2387,7 @@ static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu, if (cpu_has_xsave) memcpy(guest_xsave->region, &vcpu->arch.guest_fpu.state->xsave, - sizeof(struct xsave_struct)); + xstate_size); else { memcpy(guest_xsave->region, &vcpu->arch.guest_fpu.state->fxsave, @@ -2405,7 +2405,7 @@ static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu, if (cpu_has_xsave) memcpy(&vcpu->arch.guest_fpu.state->xsave, - guest_xsave->region, sizeof(struct xsave_struct)); + guest_xsave->region, xstate_size); else { if (xstate_bv & ~XSTATE_FPSSE) return -EINVAL; -- 1.7.2.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
