2023-05-29 04:22:14

by Isaku Yamahata

[permalink] [raw]
Subject: [PATCH v14 003/113] KVM: x86/vmx: Refactor KVM VMX module init/exit functions

From: Isaku Yamahata <[email protected]>

Currently, KVM VMX module initialization/exit functions are a single
function each. Refactor KVM VMX module initialization functions into KVM
common part and VMX part so that TDX specific part can be added cleanly.
Opportunistically refactor module exit function as well.

The current module initialization flow is,
0.) Check if VMX is supported,
1.) hyper-v specific initialization,
2.) system-wide x86 specific and vendor specific initialization,
3.) Final VMX specific system-wide initialization,
4.) calculate the sizes of VMX kvm structure and VMX vcpu structure,
5.) report those sizes to the KVM common layer and KVM common
initialization

Refactor the KVM VMX module initialization function into functions with a
wrapper function to separate VMX logic in vmx.c from a file, main.c, common
among VMX and TDX. Introduce a wrapper function for vmx_init().

The KVM architecture common layer allocates struct kvm with reported size
for architecture-specific code. The KVM VMX module defines its structure
as struct vmx_kvm { struct kvm; VMX specific members;} and uses it as
struct vmx kvm. Similar for vcpu structure. TDX KVM patches will define
TDX specific kvm and vcpu structures.

The current module exit function is also a single function, a combination
of VMX specific logic and common KVM logic. Refactor it into VMX specific
logic and KVM common logic. This is just refactoring to keep the VMX
specific logic in vmx.c from main.c.

Signed-off-by: Isaku Yamahata <[email protected]>
---
arch/x86/kvm/vmx/main.c | 50 +++++++++++++++++++++++++++++++++++
arch/x86/kvm/vmx/vmx.c | 54 +++++---------------------------------
arch/x86/kvm/vmx/x86_ops.h | 13 ++++++++-
3 files changed, 68 insertions(+), 49 deletions(-)

diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index a59559ff140e..791ee271393d 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -165,3 +165,53 @@ struct kvm_x86_init_ops vt_init_ops __initdata = {
.runtime_ops = &vt_x86_ops,
.pmu_ops = &intel_pmu_ops,
};
+
+static int __init vt_init(void)
+{
+ unsigned int vcpu_size, vcpu_align;
+ int r;
+
+ if (!kvm_is_vmx_supported())
+ return -EOPNOTSUPP;
+
+ /*
+ * Note, hv_init_evmcs() touches only VMX knobs, i.e. there's nothing
+ * to unwind if a later step fails.
+ */
+ hv_init_evmcs();
+
+ r = kvm_x86_vendor_init(&vt_init_ops);
+ if (r)
+ return r;
+
+ r = vmx_init();
+ if (r)
+ goto err_vmx_init;
+
+ /*
+ * Common KVM initialization _must_ come last, after this, /dev/kvm is
+ * exposed to userspace!
+ */
+ vcpu_size = sizeof(struct vcpu_vmx);
+ vcpu_align = __alignof__(struct vcpu_vmx);
+ r = kvm_init(vcpu_size, vcpu_align, THIS_MODULE);
+ if (r)
+ goto err_kvm_init;
+
+ return 0;
+
+err_kvm_init:
+ vmx_exit();
+err_vmx_init:
+ kvm_x86_vendor_exit();
+ return r;
+}
+module_init(vt_init);
+
+static void vt_exit(void)
+{
+ kvm_exit();
+ kvm_x86_vendor_exit();
+ vmx_exit();
+}
+module_exit(vt_exit);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ed7bf8fc55a8..9e4def64495b 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -554,7 +554,7 @@ static int hv_enable_l2_tlb_flush(struct kvm_vcpu *vcpu)
return 0;
}

-static __init void hv_init_evmcs(void)
+__init void hv_init_evmcs(void)
{
int cpu;

@@ -590,7 +590,7 @@ static __init void hv_init_evmcs(void)
}
}

-static void hv_reset_evmcs(void)
+void hv_reset_evmcs(void)
{
struct hv_vp_assist_page *vp_ap;

@@ -614,10 +614,6 @@ static void hv_reset_evmcs(void)
vp_ap->current_nested_vmcs = 0;
vp_ap->enlighten_vmentry = 0;
}
-
-#else /* IS_ENABLED(CONFIG_HYPERV) */
-static void hv_init_evmcs(void) {}
-static void hv_reset_evmcs(void) {}
#endif /* IS_ENABLED(CONFIG_HYPERV) */

/*
@@ -2715,7 +2711,7 @@ static int setup_vmcs_config(struct vmcs_config *vmcs_conf,
return 0;
}

-static bool kvm_is_vmx_supported(void)
+bool kvm_is_vmx_supported(void)
{
int cpu = raw_smp_processor_id();

@@ -8381,7 +8377,7 @@ static void vmx_cleanup_l1d_flush(void)
l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO;
}

-static void __vmx_exit(void)
+void vmx_exit(void)
{
allow_smaller_maxphyaddr = false;

@@ -8392,32 +8388,10 @@ static void __vmx_exit(void)
vmx_cleanup_l1d_flush();
}

-static void vmx_exit(void)
-{
- kvm_exit();
- kvm_x86_vendor_exit();
-
- __vmx_exit();
-}
-module_exit(vmx_exit);
-
-static int __init vmx_init(void)
+int __init vmx_init(void)
{
int r, cpu;

- if (!kvm_is_vmx_supported())
- return -EOPNOTSUPP;
-
- /*
- * Note, hv_init_evmcs() touches only VMX knobs, i.e. there's nothing
- * to unwind if a later step fails.
- */
- hv_init_evmcs();
-
- r = kvm_x86_vendor_init(&vt_init_ops);
- if (r)
- return r;
-
/*
* Must be called after common x86 init so enable_ept is properly set
* up. Hand the parameter mitigation value in which was stored in
@@ -8427,7 +8401,7 @@ static int __init vmx_init(void)
*/
r = vmx_setup_l1d_flush(vmentry_l1d_flush_param);
if (r)
- goto err_l1d_flush;
+ return r;

vmx_setup_fb_clear_ctrl();

@@ -8448,21 +8422,5 @@ static int __init vmx_init(void)
if (!enable_ept)
allow_smaller_maxphyaddr = true;

- /*
- * Common KVM initialization _must_ come last, after this, /dev/kvm is
- * exposed to userspace!
- */
- r = kvm_init(sizeof(struct vcpu_vmx), __alignof__(struct vcpu_vmx),
- THIS_MODULE);
- if (r)
- goto err_kvm_init;
-
return 0;
-
-err_kvm_init:
- __vmx_exit();
-err_l1d_flush:
- kvm_x86_vendor_exit();
- return r;
}
-module_init(vmx_init);
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index e9ec4d259ff5..051b5c4b5c2f 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -8,11 +8,22 @@

#include "x86.h"

-__init int vmx_hardware_setup(void);
+#if IS_ENABLED(CONFIG_HYPERV)
+__init void hv_init_evmcs(void);
+void hv_reset_evmcs(void);
+#else /* IS_ENABLED(CONFIG_HYPERV) */
+static inline void hv_init_evmcs(void) {}
+static inline void hv_reset_evmcs(void) {}
+#endif /* IS_ENABLED(CONFIG_HYPERV) */
+
+bool kvm_is_vmx_supported(void);
+int __init vmx_init(void);
+void vmx_exit(void);

extern struct kvm_x86_ops vt_x86_ops __initdata;
extern struct kvm_x86_init_ops vt_init_ops __initdata;

+__init int vmx_hardware_setup(void);
void vmx_hardware_unsetup(void);
int vmx_check_processor_compat(void);
int vmx_hardware_enable(void);
--
2.25.1



2023-05-31 02:38:12

by Zhi Wang

[permalink] [raw]
Subject: Re: [PATCH v14 003/113] KVM: x86/vmx: Refactor KVM VMX module init/exit functions

On Sun, 28 May 2023 21:18:45 -0700
[email protected] wrote:

> From: Isaku Yamahata <[email protected]>
>
> Currently, KVM VMX module initialization/exit functions are a single
> function each. Refactor KVM VMX module initialization functions into KVM
> common part and VMX part so that TDX specific part can be added cleanly.
> Opportunistically refactor module exit function as well.
>
> The current module initialization flow is,
> 0.) Check if VMX is supported,
> 1.) hyper-v specific initialization,
> 2.) system-wide x86 specific and vendor specific initialization,
> 3.) Final VMX specific system-wide initialization,
> 4.) calculate the sizes of VMX kvm structure and VMX vcpu structure,
> 5.) report those sizes to the KVM common layer and KVM common
> initialization
>
> Refactor the KVM VMX module initialization function into functions with a
> wrapper function to separate VMX logic in vmx.c from a file, main.c, common
> among VMX and TDX. Introduce a wrapper function for vmx_init().
>
> The KVM architecture common layer allocates struct kvm with reported size
> for architecture-specific code. The KVM VMX module defines its structure
> as struct vmx_kvm { struct kvm; VMX specific members;} and uses it as
> struct vmx kvm. Similar for vcpu structure. TDX KVM patches will define
> TDX specific kvm and vcpu structures.
>
> The current module exit function is also a single function, a combination
> of VMX specific logic and common KVM logic. Refactor it into VMX specific
> logic and KVM common logic. This is just refactoring to keep the VMX
> specific logic in vmx.c from main.c.
>
> Signed-off-by: Isaku Yamahata <[email protected]>
> ---
> arch/x86/kvm/vmx/main.c | 50 +++++++++++++++++++++++++++++++++++
> arch/x86/kvm/vmx/vmx.c | 54 +++++---------------------------------
> arch/x86/kvm/vmx/x86_ops.h | 13 ++++++++-
> 3 files changed, 68 insertions(+), 49 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> index a59559ff140e..791ee271393d 100644
> --- a/arch/x86/kvm/vmx/main.c
> +++ b/arch/x86/kvm/vmx/main.c
> @@ -165,3 +165,53 @@ struct kvm_x86_init_ops vt_init_ops __initdata = {
> .runtime_ops = &vt_x86_ops,
> .pmu_ops = &intel_pmu_ops,
> };
> +
> +static int __init vt_init(void)
> +{
> + unsigned int vcpu_size, vcpu_align;
> + int r;
> +
> + if (!kvm_is_vmx_supported())
> + return -EOPNOTSUPP;
> +
> + /*
> + * Note, hv_init_evmcs() touches only VMX knobs, i.e. there's nothing
> + * to unwind if a later step fails.
> + */
> + hv_init_evmcs();
> +
> + r = kvm_x86_vendor_init(&vt_init_ops);
> + if (r)
> + return r;
> +
> + r = vmx_init();
> + if (r)
> + goto err_vmx_init;
> +
> + /*
> + * Common KVM initialization _must_ come last, after this, /dev/kvm is
> + * exposed to userspace!
> + */
> + vcpu_size = sizeof(struct vcpu_vmx);
> + vcpu_align = __alignof__(struct vcpu_vmx);
> + r = kvm_init(vcpu_size, vcpu_align, THIS_MODULE);
> + if (r)
> + goto err_kvm_init;
> +
> + return 0;
> +
---------------------------------
> +err_kvm_init:
> + vmx_exit();
> +err_vmx_init:
> + kvm_x86_vendor_exit();
> + return r;
> +}
> +module_init(vt_init);
> +
----------------------------------
> +static void vt_exit(void)
> +{
> + kvm_exit();
> + kvm_x86_vendor_exit();
> + vmx_exit();
----------------------------------

It seems the exiting sequences above are a little bit different with
each other (PS: It is not a prob introduced in this patch):

vmx_exit()
kvm_x86_vendor_exit()
....

and

...
kvm_x86_vnedor_exit()
vmx_exit()

I was wondering which one should be correct. Literally, the exiting
sequence would be in reversing order of the initialization sequence.

> +}
> +module_exit(vt_exit);
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index ed7bf8fc55a8..9e4def64495b 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -554,7 +554,7 @@ static int hv_enable_l2_tlb_flush(struct kvm_vcpu *vcpu)
> return 0;
> }
>
> -static __init void hv_init_evmcs(void)
> +__init void hv_init_evmcs(void)
> {
> int cpu;
>
> @@ -590,7 +590,7 @@ static __init void hv_init_evmcs(void)
> }
> }
>
> -static void hv_reset_evmcs(void)
> +void hv_reset_evmcs(void)
> {
> struct hv_vp_assist_page *vp_ap;
>
> @@ -614,10 +614,6 @@ static void hv_reset_evmcs(void)
> vp_ap->current_nested_vmcs = 0;
> vp_ap->enlighten_vmentry = 0;
> }
> -
> -#else /* IS_ENABLED(CONFIG_HYPERV) */
> -static void hv_init_evmcs(void) {}
> -static void hv_reset_evmcs(void) {}
> #endif /* IS_ENABLED(CONFIG_HYPERV) */
>
> /*
> @@ -2715,7 +2711,7 @@ static int setup_vmcs_config(struct vmcs_config *vmcs_conf,
> return 0;
> }
>
> -static bool kvm_is_vmx_supported(void)
> +bool kvm_is_vmx_supported(void)
> {
> int cpu = raw_smp_processor_id();
>
> @@ -8381,7 +8377,7 @@ static void vmx_cleanup_l1d_flush(void)
> l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO;
> }
>
> -static void __vmx_exit(void)
> +void vmx_exit(void)
> {
> allow_smaller_maxphyaddr = false;
>
> @@ -8392,32 +8388,10 @@ static void __vmx_exit(void)
> vmx_cleanup_l1d_flush();
> }
>
> -static void vmx_exit(void)
> -{
> - kvm_exit();
> - kvm_x86_vendor_exit();
> -
> - __vmx_exit();
> -}
> -module_exit(vmx_exit);
> -
> -static int __init vmx_init(void)
> +int __init vmx_init(void)
> {
> int r, cpu;
>
> - if (!kvm_is_vmx_supported())
> - return -EOPNOTSUPP;
> -
> - /*
> - * Note, hv_init_evmcs() touches only VMX knobs, i.e. there's nothing
> - * to unwind if a later step fails.
> - */
> - hv_init_evmcs();
> -
> - r = kvm_x86_vendor_init(&vt_init_ops);
> - if (r)
> - return r;
> -
> /*
> * Must be called after common x86 init so enable_ept is properly set
> * up. Hand the parameter mitigation value in which was stored in
> @@ -8427,7 +8401,7 @@ static int __init vmx_init(void)
> */
> r = vmx_setup_l1d_flush(vmentry_l1d_flush_param);
> if (r)
> - goto err_l1d_flush;
> + return r;
>
> vmx_setup_fb_clear_ctrl();
>
> @@ -8448,21 +8422,5 @@ static int __init vmx_init(void)
> if (!enable_ept)
> allow_smaller_maxphyaddr = true;
>
> - /*
> - * Common KVM initialization _must_ come last, after this, /dev/kvm is
> - * exposed to userspace!
> - */
> - r = kvm_init(sizeof(struct vcpu_vmx), __alignof__(struct vcpu_vmx),
> - THIS_MODULE);
> - if (r)
> - goto err_kvm_init;
> -
> return 0;
> -
> -err_kvm_init:
> - __vmx_exit();
> -err_l1d_flush:
> - kvm_x86_vendor_exit();
> - return r;
> }
> -module_init(vmx_init);
> diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
> index e9ec4d259ff5..051b5c4b5c2f 100644
> --- a/arch/x86/kvm/vmx/x86_ops.h
> +++ b/arch/x86/kvm/vmx/x86_ops.h
> @@ -8,11 +8,22 @@
>
> #include "x86.h"
>
> -__init int vmx_hardware_setup(void);
> +#if IS_ENABLED(CONFIG_HYPERV)
> +__init void hv_init_evmcs(void);
> +void hv_reset_evmcs(void);
> +#else /* IS_ENABLED(CONFIG_HYPERV) */
> +static inline void hv_init_evmcs(void) {}
> +static inline void hv_reset_evmcs(void) {}
> +#endif /* IS_ENABLED(CONFIG_HYPERV) */
> +
> +bool kvm_is_vmx_supported(void);
> +int __init vmx_init(void);
> +void vmx_exit(void);
>
> extern struct kvm_x86_ops vt_x86_ops __initdata;
> extern struct kvm_x86_init_ops vt_init_ops __initdata;
>
> +__init int vmx_hardware_setup(void);
> void vmx_hardware_unsetup(void);
> int vmx_check_processor_compat(void);
> int vmx_hardware_enable(void);


2023-05-31 20:55:51

by Isaku Yamahata

[permalink] [raw]
Subject: Re: [PATCH v14 003/113] KVM: x86/vmx: Refactor KVM VMX module init/exit functions

On Wed, May 31, 2023 at 09:57:18AM +0800,
Zhi Wang <[email protected]> wrote:

> > +static int __init vt_init(void)
> > +{
> > + unsigned int vcpu_size, vcpu_align;
> > + int r;
> > +
> > + if (!kvm_is_vmx_supported())
> > + return -EOPNOTSUPP;
> > +
> > + /*
> > + * Note, hv_init_evmcs() touches only VMX knobs, i.e. there's nothing
> > + * to unwind if a later step fails.
> > + */
> > + hv_init_evmcs();
> > +
> > + r = kvm_x86_vendor_init(&vt_init_ops);
> > + if (r)
> > + return r;
> > +
> > + r = vmx_init();
> > + if (r)
> > + goto err_vmx_init;
> > +
> > + /*
> > + * Common KVM initialization _must_ come last, after this, /dev/kvm is
> > + * exposed to userspace!
> > + */
> > + vcpu_size = sizeof(struct vcpu_vmx);
> > + vcpu_align = __alignof__(struct vcpu_vmx);
> > + r = kvm_init(vcpu_size, vcpu_align, THIS_MODULE);
> > + if (r)
> > + goto err_kvm_init;
> > +
> > + return 0;
> > +
> ---------------------------------
> > +err_kvm_init:
> > + vmx_exit();
> > +err_vmx_init:
> > + kvm_x86_vendor_exit();
> > + return r;
> > +}
> > +module_init(vt_init);
> > +
> ----------------------------------
> > +static void vt_exit(void)
> > +{
> > + kvm_exit();
> > + kvm_x86_vendor_exit();
> > + vmx_exit();
> ----------------------------------
>
> It seems the exiting sequences above are a little bit different with
> each other (PS: It is not a prob introduced in this patch):
>
> vmx_exit()
> kvm_x86_vendor_exit()
> ....
>
> and
>
> ...
> kvm_x86_vnedor_exit()
> vmx_exit()
>
> I was wondering which one should be correct. Literally, the exiting
> sequence would be in reversing order of the initialization sequence.

In theory, I think kvm_x86_vendor_exit() => vmx_exit() and
vmx_init() => kvm_x86_vendor_exit() should be the right order.
But in practice, it doesn't matter and I didn't want to touch the order with
this patch series.
--
Isaku Yamahata <[email protected]>

2023-05-31 22:27:17

by Isaku Yamahata

[permalink] [raw]
Subject: Re: [PATCH v14 003/113] KVM: x86/vmx: Refactor KVM VMX module init/exit functions

On Wed, May 31, 2023 at 01:30:12PM -0700,
Isaku Yamahata <[email protected]> wrote:

> On Wed, May 31, 2023 at 09:57:18AM +0800,
> Zhi Wang <[email protected]> wrote:
>
> > > +static int __init vt_init(void)
> > > +{
> > > + unsigned int vcpu_size, vcpu_align;
> > > + int r;
> > > +
> > > + if (!kvm_is_vmx_supported())
> > > + return -EOPNOTSUPP;
> > > +
> > > + /*
> > > + * Note, hv_init_evmcs() touches only VMX knobs, i.e. there's nothing
> > > + * to unwind if a later step fails.
> > > + */
> > > + hv_init_evmcs();
> > > +
> > > + r = kvm_x86_vendor_init(&vt_init_ops);
> > > + if (r)
> > > + return r;
> > > +
> > > + r = vmx_init();
> > > + if (r)
> > > + goto err_vmx_init;
> > > +
> > > + /*
> > > + * Common KVM initialization _must_ come last, after this, /dev/kvm is
> > > + * exposed to userspace!
> > > + */
> > > + vcpu_size = sizeof(struct vcpu_vmx);
> > > + vcpu_align = __alignof__(struct vcpu_vmx);
> > > + r = kvm_init(vcpu_size, vcpu_align, THIS_MODULE);
> > > + if (r)
> > > + goto err_kvm_init;
> > > +
> > > + return 0;
> > > +
> > ---------------------------------
> > > +err_kvm_init:
> > > + vmx_exit();
> > > +err_vmx_init:
> > > + kvm_x86_vendor_exit();
> > > + return r;
> > > +}
> > > +module_init(vt_init);
> > > +
> > ----------------------------------
> > > +static void vt_exit(void)
> > > +{
> > > + kvm_exit();
> > > + kvm_x86_vendor_exit();
> > > + vmx_exit();
> > ----------------------------------
> >
> > It seems the exiting sequences above are a little bit different with
> > each other (PS: It is not a prob introduced in this patch):
> >
> > vmx_exit()
> > kvm_x86_vendor_exit()
> > ....
> >
> > and
> >
> > ...
> > kvm_x86_vnedor_exit()
> > vmx_exit()
> >
> > I was wondering which one should be correct. Literally, the exiting
> > sequence would be in reversing order of the initialization sequence.
>
> In theory, I think kvm_x86_vendor_exit() => vmx_exit() and
> vmx_init() => kvm_x86_vendor_exit() should be the right order.
> But in practice, it doesn't matter and I didn't want to touch the order with
> this patch series.

Here is the patch for it. But I'd like to hold the patch after this patch
series.

From 02c425cb96c252eecbeaf8e57dd6afd7576931b1 Mon Sep 17 00:00:00 2001
Message-Id: <02c425cb96c252eecbeaf8e57dd6afd7576931b1.1685566207.git.isaku.yamahata@intel.com>
From: Isaku Yamahata <[email protected]>
Date: Wed, 31 May 2023 13:36:10 -0700
Subject: [PATCH] KVM: VMX: Reorder vmx initialization with kvm vendor
initialization

To match vmx_exit cleanup.

Signed-off-by: Isaku Yamahata <[email protected]>
---
arch/x86/kvm/vmx/main.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 2e4667307458..a0586da86d81 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -1251,11 +1251,11 @@ static int __init vt_init(void)
__alignof__(struct vcpu_tdx));
}

- r = kvm_x86_vendor_init(&vt_init_ops);
+ r = vmx_init();
if (r)
- return r;
+ goto err_vmx_init;

- r = vmx_init();
+ r = kvm_x86_vendor_init(&vt_init_ops);
if (r)
goto err_vmx_init;

@@ -1270,9 +1270,9 @@ static int __init vt_init(void)
return 0;

err_kvm_init:
- vmx_exit();
-err_vmx_init:
kvm_x86_vendor_exit();
+err_vmx_init:
+ vmx_exit();
return r;
}
module_init(vt_init);
--
2.25.1




--
Isaku Yamahata <[email protected]>