* Re: [PATCH] x86/kvm/vmx: Fix GPF on reading vmentry_l1d_flush
[not found] ` <CA+res+Qq1uw301md02ZDPNdiEtdFHOe5VKhsUZ_ugY_LK5t2mg@mail.gmail.com>
@ 2018-08-22 8:32 ` Jinpu Wang
0 siblings, 0 replies; only message in thread
From: Jinpu Wang @ 2018-08-22 8:32 UTC (permalink / raw)
To: minoura, kvm, linux-kernel; +Cc: stable
> From: MINOURA Makoto / 箕浦 真 <minoura@valinux.co.jp>
> Date: 2018年8月22日周三 上午9:50
> Subject: [PATCH] x86/kvm/vmx: Fix GPF on reading vmentry_l1d_flush
> To: <kvm@vger.kernel.org>
> Cc: <linux-kernel@vger.kernel.org>
>
>
>
> When EPT is not enabled, reading
> /sys/module/kvm_intel/parameters/vmentry_l1d_flush causes
> general protection fault in vmentry_l1d_flush_get() due to
> access beyond the end of the array vmentry_l1d_param[].
>
> Signed-off-by: Minoura Makoto <minoura@valinux.co.jp>
> ---
> arch/x86/include/asm/vmx.h | 1 +
> arch/x86/kvm/vmx.c | 4 +++-
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
> index 95f9107449bf..c4b834b05178 100644
> --- a/arch/x86/include/asm/vmx.h
> +++ b/arch/x86/include/asm/vmx.h
> @@ -581,6 +581,7 @@ enum vmx_l1d_flush_state {
> VMENTER_L1D_FLUSH_NEVER,
> VMENTER_L1D_FLUSH_COND,
> VMENTER_L1D_FLUSH_ALWAYS,
> + VMENTER_L1D_FLUSH_PARAM_MAX = VMENTER_L1D_FLUSH_ALWAYS,
> VMENTER_L1D_FLUSH_EPT_DISABLED,
> VMENTER_L1D_FLUSH_NOT_REQUIRED,
> };
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 1519f030fd73..155ba2a9139f 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -204,6 +204,8 @@ static const struct {
> {"never", VMENTER_L1D_FLUSH_NEVER},
> {"cond", VMENTER_L1D_FLUSH_COND},
> {"always", VMENTER_L1D_FLUSH_ALWAYS},
> + {"ept-disabled", VMENTER_L1D_FLUSH_EPT_DISABLED},
> + {"not-required", VMENTER_L1D_FLUSH_NOT_REQUIRED},
> };
>
> #define L1D_CACHE_ORDER 4
> @@ -286,7 +288,7 @@ static int vmentry_l1d_flush_parse(const char *s)
> unsigned int i;
>
> if (s) {
> - for (i = 0; i < ARRAY_SIZE(vmentry_l1d_param); i++) {
> + for (i = 0; i <= VMENTER_L1D_FLUSH_PARAM_MAX; i++) {
> if (sysfs_streq(s, vmentry_l1d_param[i].option))
> return vmentry_l1d_param[i].cmd;
> }
Easy to reproduce. Thanks.
Tested-by: Jack Wang <jinpu.wang@profitbricks.com>
--
Jack Wang
Linux Kernel Developer
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