diff mbox series

[v3,1/2] KVM: VMX: Cleanup VMX basic information defines and usages

Message ID 20231030233940.438233-1-xin@zytor.com (mailing list archive)
State New, archived
Headers show
Series [v3,1/2] KVM: VMX: Cleanup VMX basic information defines and usages | expand

Commit Message

Xin Li Oct. 30, 2023, 11:39 p.m. UTC 
From: Xin Li <xin3.li@intel.com>

Define VMX basic information fields with BIT_ULL()/GENMASK_ULL(), and
replace hardcoded VMX basic numbers with these field macros.

Per Sean's ask, save the full/raw value of MSR_IA32_VMX_BASIC in the
global vmcs_config as type u64 to get rid of the hi/lo crud, and then
use VMX_BASIC helpers to extract info as needed.

Tested-by: Shan Kang <shan.kang@intel.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
---

Changes since v2:
* Simply save the full/raw value of MSR_IA32_VMX_BASIC in the global
  vmcs_config, and then use the helpers to extract info from it as
  needed (Sean Christopherson).
* Move all VMX_MISC related changes to the second patch (Kai Huang).
* Commonize memory type definitions used in the VMX files, as memory
  types are architectural.

Changes since v1:
* Don't add field shift macros unless it's really needed, extra layer
  of indirect makes it harder to read (Sean Christopherson).
* Add a static_assert() to ensure that VMX_BASIC_FEATURES_MASK doesn't
  overlap with VMX_BASIC_RESERVED_BITS (Sean Christopherson).
* read MSR_IA32_VMX_BASIC into an u64 rather than 2 u32 (Sean
  Christopherson).
* Add 2 new functions for extracting fields from VMX basic (Sean
  Christopherson).
* Drop the tools header update (Sean Christopherson).
* Move VMX basic field macros to arch/x86/include/asm/vmx.h.
---
 arch/x86/include/asm/msr-index.h |  9 ---------
 arch/x86/include/asm/vmx.h       | 20 ++++++++++++++++++--
 arch/x86/kvm/vmx/capabilities.h  |  6 ++----
 arch/x86/kvm/vmx/nested.c        | 31 +++++++++++++++++++++----------
 arch/x86/kvm/vmx/vmx.c           | 24 ++++++++++--------------
 5 files changed, 51 insertions(+), 39 deletions(-)


base-commit: 35dcbd9e47035f98f3910ae420bf10892c9bdc99

Comments

Kai Huang Oct. 31, 2023, 9:03 a.m. UTC | #1 
On Mon, 2023-10-30 at 16:39 -0700, Xin Li (Intel) wrote:
> From: Xin Li <xin3.li@intel.com>
> 
> Define VMX basic information fields with BIT_ULL()/GENMASK_ULL(), and
> replace hardcoded VMX basic numbers with these field macros.
> 
> Per Sean's ask, save the full/raw value of MSR_IA32_VMX_BASIC in the
> global vmcs_config as type u64 to get rid of the hi/lo crud, and then
> use VMX_BASIC helpers to extract info as needed.
> 

[...]

Btw, it's better to have a cover letter even for this small series and give a
lore link for old versions so that people can easily find old discussions.

>  
> +/* x86 memory types, explicitly used in VMX only */
> +#define MEM_TYPE_WB				0x6ULL
> +#define MEM_TYPE_UC				0x0ULL

The renaming of memory type macros deserves some justification in the changelog
IMHO, because it doesn't belong to what the patch title claims to do.

You can even split this part out, but will leave to Sean/Paolo.

> +
> +/* VMX_BASIC bits and bitmasks */
> +#define VMX_BASIC_32BIT_PHYS_ADDR_ONLY		BIT_ULL(48)
> +#define VMX_BASIC_INOUT				BIT_ULL(54)
> +
>  #define VMX_MISC_PREEMPTION_TIMER_RATE_MASK	0x0000001f
>  #define VMX_MISC_SAVE_EFER_LMA			0x00000020
>  #define VMX_MISC_ACTIVITY_HLT			0x00000040
> @@ -143,6 +151,16 @@ static inline u32 vmx_basic_vmcs_size(u64 vmx_basic)
>  	return (vmx_basic & GENMASK_ULL(44, 32)) >> 32;
>  }
>  
> +static inline u32 vmx_basic_vmcs_basic_cap(u64 vmx_basic)
> +{
> +	return (vmx_basic & GENMASK_ULL(63, 45)) >> 32;
> +}

Is this still needed?

> +
> +static inline u32 vmx_basic_vmcs_mem_type(u64 vmx_basic)
> +{
> +	return (vmx_basic & GENMASK_ULL(53, 50)) >> 50;
> +}

You already have VMX_BASIC_MEM_TYPE_SHIFT defined below, so it looks a little
bit odd to still use hard-coded values here.

But per Sean I agree it's quite noisy to have all these _SHIFT defined just in
order to get rid of these hard-coded values.

How about, ...

> +#define VMX_BASIC_VMCS_SIZE_SHIFT		32
> +#define VMX_BASIC_DUAL_MONITOR_TREATMENT	BIT_ULL(49)
> +#define VMX_BASIC_MEM_TYPE_SHIFT		50
> +#define VMX_BASIC_TRUE_CTLS			BIT_ULL(55)
> +
> 

... since, if I am reading correctly, the two _SHIFT above are only used ...

[...]

> @@ -6964,7 +6975,7 @@ static void nested_vmx_setup_basic(struct nested_vmx_msrs *msrs)
>  		VMCS12_REVISION |
>  		VMX_BASIC_TRUE_CTLS |
>  		((u64)VMCS12_SIZE << VMX_BASIC_VMCS_SIZE_SHIFT) |
> -		(VMX_BASIC_MEM_TYPE_WB << VMX_BASIC_MEM_TYPE_SHIFT);
> +		(MEM_TYPE_WB << VMX_BASIC_MEM_TYPE_SHIFT);
>  

... here, we can remove the two _SHIFT but define below instead:

  #define VMX_BASIC_VMCS12_SIZE	((u64)VMCS12_SIZE << 32)
  #define VMX_BASIC_MEM_TYPE_WB	(MEM_TYPE_WB << 50)

And use above two macros in nested_vmx_setup_basic()?
Xin Li Oct. 31, 2023, 5:28 p.m. UTC | #2 
On 10/31/2023 2:03 AM, Huang, Kai wrote:
> On Mon, 2023-10-30 at 16:39 -0700, Xin Li (Intel) wrote:
>> From: Xin Li <xin3.li@intel.com>
>>
>> Define VMX basic information fields with BIT_ULL()/GENMASK_ULL(), and
>> replace hardcoded VMX basic numbers with these field macros.
>>
>> Per Sean's ask, save the full/raw value of MSR_IA32_VMX_BASIC in the
>> global vmcs_config as type u64 to get rid of the hi/lo crud, and then
>> use VMX_BASIC helpers to extract info as needed.
>>
> 
> [...]
> 
> Btw, it's better to have a cover letter even for this small series and give a
> lore link for old versions so that people can easily find old discussions.

Well, this patch set has few (I would say no) logic and functionality
changes, and the change history should be it.

> 
>>   
>> +/* x86 memory types, explicitly used in VMX only */
>> +#define MEM_TYPE_WB				0x6ULL
>> +#define MEM_TYPE_UC				0x0ULL
> 
> The renaming of memory type macros deserves some justification in the changelog
> IMHO, because it doesn't belong to what the patch title claims to do.

I thought about it, however the changes are more of how these 2 memory
type macros are used, which is still cleanup.

> 
> You can even split this part out, but will leave to Sean/Paolo.

My point too :)

> 
>> +
>> +/* VMX_BASIC bits and bitmasks */
>> +#define VMX_BASIC_32BIT_PHYS_ADDR_ONLY		BIT_ULL(48)
>> +#define VMX_BASIC_INOUT				BIT_ULL(54)
>> +
>>   #define VMX_MISC_PREEMPTION_TIMER_RATE_MASK	0x0000001f
>>   #define VMX_MISC_SAVE_EFER_LMA			0x00000020
>>   #define VMX_MISC_ACTIVITY_HLT			0x00000040
>> @@ -143,6 +151,16 @@ static inline u32 vmx_basic_vmcs_size(u64 vmx_basic)
>>   	return (vmx_basic & GENMASK_ULL(44, 32)) >> 32;
>>   }
>>   
>> +static inline u32 vmx_basic_vmcs_basic_cap(u64 vmx_basic)
>> +{
>> +	return (vmx_basic & GENMASK_ULL(63, 45)) >> 32;
>> +}
> 
> Is this still needed?

no.

> 
>> +
>> +static inline u32 vmx_basic_vmcs_mem_type(u64 vmx_basic)
>> +{
>> +	return (vmx_basic & GENMASK_ULL(53, 50)) >> 50;
>> +}
> 
> You already have VMX_BASIC_MEM_TYPE_SHIFT defined below, so it looks a little
> bit odd to still use hard-coded values here.
> 
> But per Sean I agree it's quite noisy to have all these _SHIFT defined just in
> order to get rid of these hard-coded values.
> 
> How about, ...
> 
>> +#define VMX_BASIC_VMCS_SIZE_SHIFT		32
>> +#define VMX_BASIC_DUAL_MONITOR_TREATMENT	BIT_ULL(49)
>> +#define VMX_BASIC_MEM_TYPE_SHIFT		50
>> +#define VMX_BASIC_TRUE_CTLS			BIT_ULL(55)
>> +
>>
> 
> ... since, if I am reading correctly, the two _SHIFT above are only used ...
> 
> [...]
> 
>> @@ -6964,7 +6975,7 @@ static void nested_vmx_setup_basic(struct nested_vmx_msrs *msrs)
>>   		VMCS12_REVISION |
>>   		VMX_BASIC_TRUE_CTLS |
>>   		((u64)VMCS12_SIZE << VMX_BASIC_VMCS_SIZE_SHIFT) |
>> -		(VMX_BASIC_MEM_TYPE_WB << VMX_BASIC_MEM_TYPE_SHIFT);
>> +		(MEM_TYPE_WB << VMX_BASIC_MEM_TYPE_SHIFT);
>>   
> 
> ... here, we can remove the two _SHIFT but define below instead:
> 
>    #define VMX_BASIC_VMCS12_SIZE	((u64)VMCS12_SIZE << 32)
>    #define VMX_BASIC_MEM_TYPE_WB	(MEM_TYPE_WB << 50)

I personally don't like such names, unless we can name them in a better
way.

> 
> And use above two macros in nested_vmx_setup_basic()?
> 
Thanks!
     Xin
Li, Xin3 Jan. 12, 2024, 9:51 a.m. UTC | #3 
> >> @@ -6964,7 +6975,7 @@ static void nested_vmx_setup_basic(struct
> nested_vmx_msrs *msrs)
> >>   		VMCS12_REVISION |
> >>   		VMX_BASIC_TRUE_CTLS |
> >>   		((u64)VMCS12_SIZE << VMX_BASIC_VMCS_SIZE_SHIFT) |
> >> -		(VMX_BASIC_MEM_TYPE_WB <<
> VMX_BASIC_MEM_TYPE_SHIFT);
> >> +		(MEM_TYPE_WB << VMX_BASIC_MEM_TYPE_SHIFT);
> >>
> >
> > ... here, we can remove the two _SHIFT but define below instead:
> >
> >    #define VMX_BASIC_VMCS12_SIZE	((u64)VMCS12_SIZE << 32)
> >    #define VMX_BASIC_MEM_TYPE_WB	(MEM_TYPE_WB << 50)
> 
> I personally don't like such names, unless we can name them in a better way.
> 
> >
> > And use above two macros in nested_vmx_setup_basic()?

A second thought on this, I agree this is better.  And I will post v4.

Thanks!
    Xin
diff mbox series

Patch

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 8bcbebb56b8f..d83195f53e33 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -1084,15 +1084,6 @@ 
 #define MSR_IA32_VMX_VMFUNC             0x00000491
 #define MSR_IA32_VMX_PROCBASED_CTLS3	0x00000492
 
-/* VMX_BASIC bits and bitmasks */
-#define VMX_BASIC_VMCS_SIZE_SHIFT	32
-#define VMX_BASIC_TRUE_CTLS		(1ULL << 55)
-#define VMX_BASIC_64		0x0001000000000000LLU
-#define VMX_BASIC_MEM_TYPE_SHIFT	50
-#define VMX_BASIC_MEM_TYPE_MASK	0x003c000000000000LLU
-#define VMX_BASIC_MEM_TYPE_WB	6LLU
-#define VMX_BASIC_INOUT		0x0040000000000000LLU
-
 /* Resctrl MSRs: */
 /* - Intel: */
 #define MSR_IA32_L3_QOS_CFG		0xc81
diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 0e73616b82f3..088b75d97c38 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -120,6 +120,14 @@ 
 
 #define VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR	0x000011ff
 
+/* x86 memory types, explicitly used in VMX only */
+#define MEM_TYPE_WB				0x6ULL
+#define MEM_TYPE_UC				0x0ULL
+
+/* VMX_BASIC bits and bitmasks */
+#define VMX_BASIC_32BIT_PHYS_ADDR_ONLY		BIT_ULL(48)
+#define VMX_BASIC_INOUT				BIT_ULL(54)
+
 #define VMX_MISC_PREEMPTION_TIMER_RATE_MASK	0x0000001f
 #define VMX_MISC_SAVE_EFER_LMA			0x00000020
 #define VMX_MISC_ACTIVITY_HLT			0x00000040
@@ -143,6 +151,16 @@  static inline u32 vmx_basic_vmcs_size(u64 vmx_basic)
 	return (vmx_basic & GENMASK_ULL(44, 32)) >> 32;
 }
 
+static inline u32 vmx_basic_vmcs_basic_cap(u64 vmx_basic)
+{
+	return (vmx_basic & GENMASK_ULL(63, 45)) >> 32;
+}
+
+static inline u32 vmx_basic_vmcs_mem_type(u64 vmx_basic)
+{
+	return (vmx_basic & GENMASK_ULL(53, 50)) >> 50;
+}
+
 static inline int vmx_misc_preemption_timer_rate(u64 vmx_misc)
 {
 	return vmx_misc & VMX_MISC_PREEMPTION_TIMER_RATE_MASK;
@@ -505,8 +523,6 @@  enum vmcs_field {
 #define VMX_EPTP_PWL_5				0x20ull
 #define VMX_EPTP_AD_ENABLE_BIT			(1ull << 6)
 #define VMX_EPTP_MT_MASK			0x7ull
-#define VMX_EPTP_MT_WB				0x6ull
-#define VMX_EPTP_MT_UC				0x0ull
 #define VMX_EPT_READABLE_MASK			0x1ull
 #define VMX_EPT_WRITABLE_MASK			0x2ull
 #define VMX_EPT_EXECUTABLE_MASK			0x4ull
diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
index 41a4533f9989..86ce8bb96bed 100644
--- a/arch/x86/kvm/vmx/capabilities.h
+++ b/arch/x86/kvm/vmx/capabilities.h
@@ -54,9 +54,7 @@  struct nested_vmx_msrs {
 };
 
 struct vmcs_config {
-	int size;
-	u32 basic_cap;
-	u32 revision_id;
+	u64 basic;
 	u32 pin_based_exec_ctrl;
 	u32 cpu_based_exec_ctrl;
 	u32 cpu_based_2nd_exec_ctrl;
@@ -76,7 +74,7 @@  extern struct vmx_capability vmx_capability __ro_after_init;
 
 static inline bool cpu_has_vmx_basic_inout(void)
 {
-	return	(((u64)vmcs_config.basic_cap << 32) & VMX_BASIC_INOUT);
+	return	vmcs_config.basic & VMX_BASIC_INOUT;
 }
 
 static inline bool cpu_has_virtual_nmis(void)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index c5ec0ef51ff7..23704f8d9035 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -1201,23 +1201,34 @@  static bool is_bitwise_subset(u64 superset, u64 subset, u64 mask)
 	return (superset | subset) == superset;
 }
 
+#define VMX_BASIC_VMCS_SIZE_SHIFT		32
+#define VMX_BASIC_DUAL_MONITOR_TREATMENT	BIT_ULL(49)
+#define VMX_BASIC_MEM_TYPE_SHIFT		50
+#define VMX_BASIC_TRUE_CTLS			BIT_ULL(55)
+
+#define VMX_BASIC_FEATURES_MASK			\
+	(VMX_BASIC_DUAL_MONITOR_TREATMENT |	\
+	 VMX_BASIC_INOUT |			\
+	 VMX_BASIC_TRUE_CTLS)
+
+#define VMX_BASIC_RESERVED_BITS			\
+	(GENMASK_ULL(63, 56) | GENMASK_ULL(47, 45) | BIT_ULL(31))
+
 static int vmx_restore_vmx_basic(struct vcpu_vmx *vmx, u64 data)
 {
-	const u64 feature_and_reserved =
-		/* feature (except bit 48; see below) */
-		BIT_ULL(49) | BIT_ULL(54) | BIT_ULL(55) |
-		/* reserved */
-		BIT_ULL(31) | GENMASK_ULL(47, 45) | GENMASK_ULL(63, 56);
 	u64 vmx_basic = vmcs_config.nested.basic;
 
-	if (!is_bitwise_subset(vmx_basic, data, feature_and_reserved))
+	static_assert(!(VMX_BASIC_FEATURES_MASK & VMX_BASIC_RESERVED_BITS));
+
+	if (!is_bitwise_subset(vmx_basic, data,
+			       VMX_BASIC_FEATURES_MASK | VMX_BASIC_RESERVED_BITS))
 		return -EINVAL;
 
 	/*
 	 * KVM does not emulate a version of VMX that constrains physical
 	 * addresses of VMX structures (e.g. VMCS) to 32-bits.
 	 */
-	if (data & BIT_ULL(48))
+	if (data & VMX_BASIC_32BIT_PHYS_ADDR_ONLY)
 		return -EINVAL;
 
 	if (vmx_basic_vmcs_revision_id(vmx_basic) !=
@@ -2690,11 +2701,11 @@  static bool nested_vmx_check_eptp(struct kvm_vcpu *vcpu, u64 new_eptp)
 
 	/* Check for memory type validity */
 	switch (new_eptp & VMX_EPTP_MT_MASK) {
-	case VMX_EPTP_MT_UC:
+	case MEM_TYPE_UC:
 		if (CC(!(vmx->nested.msrs.ept_caps & VMX_EPTP_UC_BIT)))
 			return false;
 		break;
-	case VMX_EPTP_MT_WB:
+	case MEM_TYPE_WB:
 		if (CC(!(vmx->nested.msrs.ept_caps & VMX_EPTP_WB_BIT)))
 			return false;
 		break;
@@ -6964,7 +6975,7 @@  static void nested_vmx_setup_basic(struct nested_vmx_msrs *msrs)
 		VMCS12_REVISION |
 		VMX_BASIC_TRUE_CTLS |
 		((u64)VMCS12_SIZE << VMX_BASIC_VMCS_SIZE_SHIFT) |
-		(VMX_BASIC_MEM_TYPE_WB << VMX_BASIC_MEM_TYPE_SHIFT);
+		(MEM_TYPE_WB << VMX_BASIC_MEM_TYPE_SHIFT);
 
 	if (cpu_has_vmx_basic_inout())
 		msrs->basic |= VMX_BASIC_INOUT;
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index be20a60047b1..9caed798d070 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2568,13 +2568,13 @@  static u64 adjust_vmx_controls64(u64 ctl_opt, u32 msr)
 static int setup_vmcs_config(struct vmcs_config *vmcs_conf,
 			     struct vmx_capability *vmx_cap)
 {
-	u32 vmx_msr_low, vmx_msr_high;
 	u32 _pin_based_exec_control = 0;
 	u32 _cpu_based_exec_control = 0;
 	u32 _cpu_based_2nd_exec_control = 0;
 	u64 _cpu_based_3rd_exec_control = 0;
 	u32 _vmexit_control = 0;
 	u32 _vmentry_control = 0;
+	u64 basic_msr;
 	u64 misc_msr;
 	int i;
 
@@ -2693,29 +2693,25 @@  static int setup_vmcs_config(struct vmcs_config *vmcs_conf,
 		_vmexit_control &= ~x_ctrl;
 	}
 
-	rdmsr(MSR_IA32_VMX_BASIC, vmx_msr_low, vmx_msr_high);
+	rdmsrl(MSR_IA32_VMX_BASIC, basic_msr);
 
 	/* IA-32 SDM Vol 3B: VMCS size is never greater than 4kB. */
-	if ((vmx_msr_high & 0x1fff) > PAGE_SIZE)
+	if ((vmx_basic_vmcs_size(basic_msr) > PAGE_SIZE))
 		return -EIO;
 
 #ifdef CONFIG_X86_64
 	/* IA-32 SDM Vol 3B: 64-bit CPUs always have VMX_BASIC_MSR[48]==0. */
-	if (vmx_msr_high & (1u<<16))
+	if (basic_msr & VMX_BASIC_32BIT_PHYS_ADDR_ONLY)
 		return -EIO;
 #endif
 
 	/* Require Write-Back (WB) memory type for VMCS accesses. */
-	if (((vmx_msr_high >> 18) & 15) != 6)
+	if (vmx_basic_vmcs_mem_type(basic_msr) != MEM_TYPE_WB)
 		return -EIO;
 
 	rdmsrl(MSR_IA32_VMX_MISC, misc_msr);
 
-	vmcs_conf->size = vmx_msr_high & 0x1fff;
-	vmcs_conf->basic_cap = vmx_msr_high & ~0x1fff;
-
-	vmcs_conf->revision_id = vmx_msr_low;
-
+	vmcs_conf->basic = basic_msr;
 	vmcs_conf->pin_based_exec_ctrl = _pin_based_exec_control;
 	vmcs_conf->cpu_based_exec_ctrl = _cpu_based_exec_control;
 	vmcs_conf->cpu_based_2nd_exec_ctrl = _cpu_based_2nd_exec_control;
@@ -2865,13 +2861,13 @@  struct vmcs *alloc_vmcs_cpu(bool shadow, int cpu, gfp_t flags)
 	if (!pages)
 		return NULL;
 	vmcs = page_address(pages);
-	memset(vmcs, 0, vmcs_config.size);
+	memset(vmcs, 0, vmx_basic_vmcs_size(vmcs_config.basic));
 
 	/* KVM supports Enlightened VMCS v1 only */
 	if (kvm_is_using_evmcs())
 		vmcs->hdr.revision_id = KVM_EVMCS_VERSION;
 	else
-		vmcs->hdr.revision_id = vmcs_config.revision_id;
+		vmcs->hdr.revision_id = vmx_basic_vmcs_revision_id(vmcs_config.basic);
 
 	if (shadow)
 		vmcs->hdr.shadow_vmcs = 1;
@@ -2964,7 +2960,7 @@  static __init int alloc_kvm_area(void)
 		 * physical CPU.
 		 */
 		if (kvm_is_using_evmcs())
-			vmcs->hdr.revision_id = vmcs_config.revision_id;
+			vmcs->hdr.revision_id = vmx_basic_vmcs_revision_id(vmcs_config.basic);
 
 		per_cpu(vmxarea, cpu) = vmcs;
 	}
@@ -3366,7 +3362,7 @@  static int vmx_get_max_ept_level(void)
 
 u64 construct_eptp(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level)
 {
-	u64 eptp = VMX_EPTP_MT_WB;
+	u64 eptp = MEM_TYPE_WB;
 
 	eptp |= (root_level == 5) ? VMX_EPTP_PWL_5 : VMX_EPTP_PWL_4;