* Re: [PATCH] vmx: add missing entries in the l1d_param array
[not found] <jpgd0ub4czi.fsf@linux.bootlegged.copy>
@ 2018-08-22 11:41 ` Paolo Bonzini
2018-08-22 11:46 ` Paolo Bonzini
1 sibling, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2018-08-22 11:41 UTC (permalink / raw)
To: Bandan Das, kvm ML
Cc: Marcelo Tosatti, Radim Krčmář, linux-kernel
On 21/08/2018 23:38, Bandan Das wrote:
>
> This can cause a host crash if an access attempts
> to reach the missing entry. Future-proof the get
> function against any overflows as well.
>
> Signed-off-by: Bandan Das <bsd@redhat.com>
> ---
> arch/x86/kvm/vmx.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 46b428c0990e..42c27406b63e 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -203,6 +203,8 @@ static const struct {
> {"never", VMENTER_L1D_FLUSH_NEVER},
> {"cond", VMENTER_L1D_FLUSH_COND},
> {"always", VMENTER_L1D_FLUSH_ALWAYS},
> + {"disabled", VMENTER_L1D_FLUSH_EPT_DISABLED},
> + {"not required", VMENTER_L1D_FLUSH_NOT_REQUIRED},
> };
>
> #define L1D_CACHE_ORDER 4
> @@ -323,7 +325,17 @@ static int vmentry_l1d_flush_set(const char *s, const struct kernel_param *kp)
>
> static int vmentry_l1d_flush_get(char *s, const struct kernel_param *kp)
> {
> - return sprintf(s, "%s\n", vmentry_l1d_param[l1tf_vmx_mitigation].option);
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(vmentry_l1d_param); i++) {
> + if (vmentry_l1d_param[i].cmd == l1tf_vmx_mitigation)
> + break;
> + }
> +
> + if (i == ARRAY_SIZE(vmentry_l1d_param))
> + return -EINVAL;
> +
> + return sprintf(s, "%s\n", vmentry_l1d_param[i].option);
> }
>
> static const struct kernel_param_ops vmentry_l1d_flush_ops = {
>
Queued, thanks.
Paolo
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [PATCH] vmx: add missing entries in the l1d_param array
[not found] <jpgd0ub4czi.fsf@linux.bootlegged.copy>
2018-08-22 11:41 ` [PATCH] vmx: add missing entries in the l1d_param array Paolo Bonzini
@ 2018-08-22 11:46 ` Paolo Bonzini
1 sibling, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2018-08-22 11:46 UTC (permalink / raw)
To: Bandan Das, kvm ML
Cc: Marcelo Tosatti, Radim Krčmář, linux-kernel
On 21/08/2018 23:38, Bandan Das wrote:
>
> This can cause a host crash if an access attempts
> to reach the missing entry. Future-proof the get
> function against any overflows as well.
>
> Signed-off-by: Bandan Das <bsd@redhat.com>
> ---
> arch/x86/kvm/vmx.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 46b428c0990e..42c27406b63e 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -203,6 +203,8 @@ static const struct {
> {"never", VMENTER_L1D_FLUSH_NEVER},
> {"cond", VMENTER_L1D_FLUSH_COND},
> {"always", VMENTER_L1D_FLUSH_ALWAYS},
> + {"disabled", VMENTER_L1D_FLUSH_EPT_DISABLED},
> + {"not required", VMENTER_L1D_FLUSH_NOT_REQUIRED},
> };
>
> #define L1D_CACHE_ORDER 4
> @@ -323,7 +325,17 @@ static int vmentry_l1d_flush_set(const char *s, const struct kernel_param *kp)
>
> static int vmentry_l1d_flush_get(char *s, const struct kernel_param *kp)
> {
> - return sprintf(s, "%s\n", vmentry_l1d_param[l1tf_vmx_mitigation].option);
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(vmentry_l1d_param); i++) {
> + if (vmentry_l1d_param[i].cmd == l1tf_vmx_mitigation)
> + break;
> + }
> +
> + if (i == ARRAY_SIZE(vmentry_l1d_param))
> + return -EINVAL;
> +
> + return sprintf(s, "%s\n", vmentry_l1d_param[i].option);
> }
>
> static const struct kernel_param_ops vmentry_l1d_flush_ops = {
>
Hmm, actually the two missing entries must be rejected by
vmentry_l1d_flush_parse. I've fixed up the patch since I'm going to
send a pull request to Linus today.
Paolo
^ permalink raw reply [flat|nested] 2+ messages in thread