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

Xin Li (Intel)
2023-10-30T23:40:54Z

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(-)

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;

base-commit: 35dcbd9e47035f98f3910ae420bf10892c9bdc99
--
2.41.0