Re: [PATCH] KVM: SVM: Do not issue virtual VMLOAD/VMSAVE supported-message

From: Radim KrÄmÃÅ
Date: Wed Sep 13 2017 - 10:06:19 EST


2017-09-05 19:06+0200, Borislav Petkov:
> From: Borislav Petkov <bp@xxxxxxx>
>
> There's no need to issue that everytime during boot - we have the
> /proc/cpuinfo flag for people and software to query.
>
> Signed-off-by: Borislav Petkov <bp@xxxxxxx>
> Cc: Janakarajan Natarajan <Janakarajan.Natarajan@xxxxxxx>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
> ---
> arch/x86/kvm/svm.c | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 8dbd8dbc83eb..f25e5b930932 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -1101,11 +1101,8 @@ static __init int svm_hardware_setup(void)
> if (vls) {
> if (!npt_enabled ||
> !boot_cpu_has(X86_FEATURE_V_VMSAVE_VMLOAD) ||
> - !IS_ENABLED(CONFIG_X86_64)) {
> + !IS_ENABLED(CONFIG_X86_64))
> vls = false;
> - } else {
> - pr_info("Virtual VMLOAD VMSAVE supported\n");

SVM prints more offending messages on boot, so I'd do all one go.
I am thinking of collocating the info instead as the information might
prevent one round of asking for SVM features.
---8<---
Subject: [PATCH] KVM: SVM: print enabled features on one line

The information might be useful for debugging, but having each feature
present itself is needlessly verbose.

Signed-off-by: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
---
arch/x86/kvm/svm.c | 56 ++++++++++++++++++------------------------------------
1 file changed, 19 insertions(+), 37 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index af54327b9017..1901815777d0 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1078,10 +1078,8 @@ static __init int svm_hardware_setup(void)
kvm_tsc_scaling_ratio_frac_bits = 32;
}

- if (nested) {
- printk(KERN_INFO "kvm: Nested Virtualization enabled\n");
+ if (nested)
kvm_enable_efer_bits(EFER_SVME | EFER_LMSLE);
- }

for_each_possible_cpu(cpu) {
r = svm_cpu_init(cpu);
@@ -1089,48 +1087,32 @@ static __init int svm_hardware_setup(void)
goto err;
}

- if (!boot_cpu_has(X86_FEATURE_NPT))
- npt_enabled = false;
-
- if (npt_enabled && !npt) {
- printk(KERN_INFO "kvm: Nested Paging disabled\n");
+ if (!boot_cpu_has(X86_FEATURE_NPT) || !npt)
npt_enabled = false;
- }

- if (npt_enabled) {
- printk(KERN_INFO "kvm: Nested Paging enabled\n");
+ if (npt_enabled)
kvm_enable_tdp();
- } else
+ else
kvm_disable_tdp();

- if (avic) {
- if (!npt_enabled ||
- !boot_cpu_has(X86_FEATURE_AVIC) ||
- !IS_ENABLED(CONFIG_X86_LOCAL_APIC)) {
- avic = false;
- } else {
- pr_info("AVIC enabled\n");
+ if (!npt_enabled ||
+ !boot_cpu_has(X86_FEATURE_AVIC) ||
+ !IS_ENABLED(CONFIG_X86_LOCAL_APIC))
+ avic = false;

- amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier);
- }
- }
+ if (avic)
+ amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier);

- if (vls) {
- if (!npt_enabled ||
- !boot_cpu_has(X86_FEATURE_V_VMSAVE_VMLOAD) ||
- !IS_ENABLED(CONFIG_X86_64)) {
- vls = false;
- } else {
- pr_info("Virtual VMLOAD VMSAVE supported\n");
- }
- }
+ if (!npt_enabled ||
+ !boot_cpu_has(X86_FEATURE_V_VMSAVE_VMLOAD) ||
+ !IS_ENABLED(CONFIG_X86_64))
+ vls = false;

- if (vgif) {
- if (!boot_cpu_has(X86_FEATURE_VGIF))
- vgif = false;
- else
- pr_info("Virtual GIF supported\n");
- }
+ if (!boot_cpu_has(X86_FEATURE_VGIF))
+ vgif = false;
+
+ pr_info("SVM nested=%d npt=%d avic=%d vls=%d vgif=%d\n",
+ nested, npt_enabled, avic, vls, vgif);

return 0;

--
2.14.1