[MODERATED] [PATCH v4 5/8] [PATCH v4 5/8] Linux Patch #5

[MODERATED] [PATCH v4 5/8] [PATCH v4 5/8] Linux Patch #5

[konrad.wilk]

.. to help find the MSR on either the guest or host
MSR list.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/x86/kvm/vmx.c | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 3649bf3b3b82..f9d70b3e9fcd 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2376,9 +2376,20 @@ static void clear_atomic_switch_msr_special(struct vcpu_vmx *vmx,
 	vm_exit_controls_clearbit(vmx, exit);
 }
 
+static int find_msr(struct vmx_msrs *m, unsigned msr)
+{
+	unsigned int i;
+
+	for (i = 0; i < m->nr; ++i) {
+		if (m->val[i].index == msr)
+			return i;
+	}
+	return -ENOENT;
+}
+
 static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
 {
-	unsigned i;
+	int i;
 	struct msr_autoload *m = &vmx->msr_autoload;
 
 	switch (msr) {
@@ -2399,11 +2410,8 @@ static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
 		}
 		break;
 	}
-	for (i = 0; i < m->guest.nr; ++i)
-		if (m->guest.val[i].index == msr)
-			break;
-
-	if (i == m->guest.nr)
+	i = find_msr(&m->guest, msr);
+	if (i < 0)
 		return;
 	--m->guest.nr;
 	--m->host.nr;
@@ -2427,7 +2435,7 @@ static void add_atomic_switch_msr_special(struct vcpu_vmx *vmx,
 static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
 				  u64 guest_val, u64 host_val)
 {
-	unsigned i;
+	int i;
 	struct msr_autoload *m = &vmx->msr_autoload;
 
 	switch (msr) {
@@ -2462,16 +2470,13 @@ static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
 		wrmsrl(MSR_IA32_PEBS_ENABLE, 0);
 	}
 
-	for (i = 0; i < m->guest.nr; ++i)
-		if (m->guest.val[i].index == msr)
-			break;
-
+	i = find_msr(&m->guest, msr);
 	if (i == NR_AUTOLOAD_MSRS) {
 		printk_once(KERN_WARNING "Not enough msr switch entries. "
 				"Can't add msr %x\n", msr);
 		return;
-	} else if (i == m->guest.nr) {
-		++m->guest.nr;
+	} else if (i < 0) {
+		i = m->guest.nr++;
 		++m->host.nr;
 		vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr);
 		vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->host.nr);
-- 
2.14.3

[MODERATED] Re: [PATCH v4 5/8] [PATCH v4 5/8] Linux Patch #5

[Borislav Petkov]

On Sat, Jun 23, 2018 at 09:54:19AM -0400, speck for konrad.wilk_at_oracle.com wrote:
> x86/KVM/VMX: Add find_msr helper function
> 
> .. to help find the MSR on either the guest or host
> MSR list.
> 
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
>  arch/x86/kvm/vmx.c | 31 ++++++++++++++++++-------------
>  1 file changed, 18 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 3649bf3b3b82..f9d70b3e9fcd 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -2376,9 +2376,20 @@ static void clear_atomic_switch_msr_special(struct vcpu_vmx *vmx,
>  	vm_exit_controls_clearbit(vmx, exit);
>  }
>  
> +static int find_msr(struct vmx_msrs *m, unsigned msr)

WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
#31: FILE: arch/x86/kvm/vmx.c:2379:
+static int find_msr(struct vmx_msrs *m, unsigned msr)

Please integrate scripts/checkpatch.pl into your patch creation
workflow. Some of the warnings/errors *actually* make sense.

> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < m->nr; ++i) {
> +		if (m->val[i].index == msr)
> +			return i;
> +	}
> +	return -ENOENT;
> +}
> +
>  static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
>  {
> -	unsigned i;
> +	int i;
>  	struct msr_autoload *m = &vmx->msr_autoload;
>  
>  	switch (msr) {
> @@ -2399,11 +2410,8 @@ static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
>  		}
>  		break;
>  	}
> -	for (i = 0; i < m->guest.nr; ++i)
> -		if (m->guest.val[i].index == msr)
> -			break;
> -
> -	if (i == m->guest.nr)
> +	i = find_msr(&m->guest, msr);
> +	if (i < 0)
>  		return;

<---- newline here.

>  	--m->guest.nr;
>  	--m->host.nr;

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--