[RFC PATCH 02/14] KVM: x86: Fold x86 vendor modules into the main KVM modules

From: Anish Ghulati
Date: Tue Nov 07 2023 - 15:20:32 EST

Collapse x86 vendor modules, i.e. kvm_intel and kvm_amd into kvm.ko.

Add a new vendor_exit function to kvm_x86_ops so that KVM knows which
exit function to call when exiting. Since the vendor modules no longer
exist the vendor_exit function call does not have to go through a static
call.

Expose vendor init/exit/supported functions so that they can be called
from vendor neutral KVM locations.

Signed-off-by: Anish Ghulati <aghulati@xxxxxxxxxx>
---
arch/x86/include/asm/kvm-x86-ops.h | 1 +
arch/x86/include/asm/kvm_host.h | 2 +
arch/x86/kernel/nmi.c | 2 +-
arch/x86/kvm/Kconfig | 12 ++----
arch/x86/kvm/Makefile | 10 ++---
arch/x86/kvm/svm/svm.c | 38 +++++++----------
arch/x86/kvm/vmx/vmx.c | 66 +++++++++++++-----------------
arch/x86/kvm/x86.c | 18 +++++---
arch/x86/kvm/x86.h | 15 +++++++
9 files changed, 82 insertions(+), 82 deletions(-)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index e3054e3e46d5..764be4a26a0c 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -14,6 +14,7 @@ BUILD_BUG_ON(1)
* to make a definition optional, but in this case the default will
* be __static_call_return0.
*/
+KVM_X86_OP(vendor_exit)
KVM_X86_OP(check_processor_compatibility)
KVM_X86_OP(hardware_enable)
KVM_X86_OP(hardware_disable)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index eda45a937666..e01d1aa3628c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1546,6 +1546,8 @@ static inline u16 kvm_lapic_irq_dest_mode(bool dest_mode_logical)
struct kvm_x86_ops {
const char *name;

+ void (*vendor_exit)(void);
+
int (*check_processor_compatibility)(void);

int (*hardware_enable)(void);
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index a0c551846b35..8f2ac7598912 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -565,7 +565,7 @@ DEFINE_IDTENTRY_RAW(exc_nmi_kvm_vmx)
{
exc_nmi(regs);
}
-#if IS_MODULE(CONFIG_KVM_INTEL)
+#if IS_MODULE(CONFIG_KVM) && IS_ENABLED(CONFIG_KVM_INTEL)
EXPORT_SYMBOL_GPL(asm_exc_nmi_kvm_vmx);
#endif
#endif
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 8c5fb7f57b4c..adfa57d59643 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -75,15 +75,12 @@ config KVM_WERROR
If in doubt, say "N".

config KVM_INTEL
- tristate "KVM for Intel (and compatible) processors support"
+ bool "KVM for Intel (and compatible) processors support"
depends on KVM && IA32_FEAT_CTL
help
Provides support for KVM on processors equipped with Intel's VT
extensions, a.k.a. Virtual Machine Extensions (VMX).

- To compile this as a module, choose M here: the module
- will be called kvm-intel.
-
config X86_SGX_KVM
bool "Software Guard eXtensions (SGX) Virtualization"
depends on X86_SGX && KVM_INTEL
@@ -97,20 +94,17 @@ config X86_SGX_KVM
If unsure, say N.

config KVM_AMD
- tristate "KVM for AMD processors support"
+ bool "KVM for AMD processors support"
depends on KVM && (CPU_SUP_AMD || CPU_SUP_HYGON)
help
Provides support for KVM on AMD processors equipped with the AMD-V
(SVM) extensions.

- To compile this as a module, choose M here: the module
- will be called kvm-amd.
-
config KVM_AMD_SEV
def_bool y
bool "AMD Secure Encrypted Virtualization (SEV) support"
depends on KVM_AMD && X86_64
- depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m)
+ depends on CRYPTO_DEV_SP_PSP && !(KVM=y && CRYPTO_DEV_CCP_DD=m)
help
Provides support for launching Encrypted VMs (SEV) and Encrypted VMs
with Encrypted State (SEV-ES) on AMD processors.
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index d13f1a7b7b3d..3e965c90e065 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -21,20 +21,18 @@ kvm-$(CONFIG_X86_64) += mmu/tdp_iter.o mmu/tdp_mmu.o
kvm-$(CONFIG_KVM_XEN) += xen.o
kvm-$(CONFIG_KVM_SMM) += smm.o

-kvm-intel-y += vmx/vmx.o vmx/vmenter.o vmx/pmu_intel.o vmx/vmcs12.o \
+kvm-$(CONFIG_KVM_INTEL) += vmx/vmx.o vmx/vmenter.o vmx/pmu_intel.o vmx/vmcs12.o \
vmx/hyperv.o vmx/nested.o vmx/posted_intr.o
-kvm-intel-$(CONFIG_X86_SGX_KVM) += vmx/sgx.o
+kvm-$(CONFIG_X86_SGX_KVM) += vmx/sgx.o

-kvm-amd-y += svm/svm.o svm/vmenter.o svm/pmu.o svm/nested.o svm/avic.o \
+kvm-$(CONFIG_KVM_AMD) += svm/svm.o svm/vmenter.o svm/pmu.o svm/nested.o svm/avic.o \
svm/sev.o svm/hyperv.o

ifdef CONFIG_HYPERV
-kvm-amd-y += svm/svm_onhyperv.o
+kvm-$(CONFIG_KVM_AMD) += svm/svm_onhyperv.o
endif

obj-$(CONFIG_KVM) += kvm.o
-obj-$(CONFIG_KVM_INTEL) += kvm-intel.o
-obj-$(CONFIG_KVM_AMD) += kvm-amd.o

AFLAGS_svm/vmenter.o := -iquote $(obj)
$(obj)/svm/vmenter.o: $(obj)/kvm-asm-offsets.h
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 3d44e42f4f22..7fe9d11db8a6 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -52,9 +52,6 @@
#include "kvm_onhyperv.h"
#include "svm_onhyperv.h"

-MODULE_AUTHOR("Qumranet");
-MODULE_LICENSE("GPL");
-
#ifdef MODULE
static const struct x86_cpu_id svm_cpu_id[] = {
X86_MATCH_FEATURE(X86_FEATURE_SVM, NULL),
@@ -551,7 +548,7 @@ static bool __kvm_is_svm_supported(void)
return true;
}

-static bool kvm_is_svm_supported(void)
+bool kvm_is_svm_supported(void)
{
bool supported;

@@ -4873,9 +4870,21 @@ static int svm_vm_init(struct kvm *kvm)
return 0;
}

+static void __svm_exit(void)
+{
+ cpu_emergency_unregister_virt_callback(svm_emergency_disable);
+}
+
+void svm_module_exit(void)
+{
+ __svm_exit();
+}
+
static struct kvm_x86_ops svm_x86_ops __initdata = {
.name = KBUILD_MODNAME,

+ .vendor_exit = svm_module_exit,
+
.check_processor_compatibility = svm_check_processor_compat,

.hardware_unsetup = svm_hardware_unsetup,
@@ -5298,22 +5307,12 @@ static struct kvm_x86_init_ops svm_init_ops __initdata = {
.pmu_ops = &amd_pmu_ops,
};

-static void __svm_exit(void)
-{
- kvm_x86_vendor_exit();
-
- cpu_emergency_unregister_virt_callback(svm_emergency_disable);
-}
-
-static int __init svm_init(void)
+int __init svm_init(void)
{
int r;

__unused_size_checks();

- if (!kvm_is_svm_supported())
- return -EOPNOTSUPP;
-
r = kvm_x86_vendor_init(&svm_init_ops);
if (r)
return r;
@@ -5335,12 +5334,3 @@ static int __init svm_init(void)
__svm_exit();
return r;
}
-
-static void __exit svm_exit(void)
-{
- kvm_exit();
- __svm_exit();
-}
-
-module_init(svm_init)
-module_exit(svm_exit)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 65d59de3cc63..629e662b131e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -66,9 +66,6 @@
#include "x86.h"
#include "smm.h"

-MODULE_AUTHOR("Qumranet");
-MODULE_LICENSE("GPL");
-
#ifdef MODULE
static const struct x86_cpu_id vmx_cpu_id[] = {
X86_MATCH_FEATURE(X86_FEATURE_VMX, NULL),
@@ -2738,7 +2735,7 @@ static bool __kvm_is_vmx_supported(void)
return true;
}

-static bool kvm_is_vmx_supported(void)
+bool kvm_is_vmx_supported(void)
{
bool supported;

@@ -8199,9 +8196,35 @@ static void vmx_vm_destroy(struct kvm *kvm)
free_pages((unsigned long)kvm_vmx->pid_table, vmx_get_pid_table_order(kvm));
}

+static void vmx_cleanup_l1d_flush(void)
+{
+ if (vmx_l1d_flush_pages) {
+ free_pages((unsigned long)vmx_l1d_flush_pages, L1D_CACHE_ORDER);
+ vmx_l1d_flush_pages = NULL;
+ }
+ /* Restore state so sysfs ignores VMX */
+ l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO;
+}
+
+static void __vmx_exit(void)
+{
+ allow_smaller_maxphyaddr = false;
+
+ cpu_emergency_unregister_virt_callback(vmx_emergency_disable);
+
+ vmx_cleanup_l1d_flush();
+}
+
+void vmx_module_exit(void)
+{
+ __vmx_exit();
+}
+
static struct kvm_x86_ops vmx_x86_ops __initdata = {
.name = KBUILD_MODNAME,

+ .vendor_exit = vmx_module_exit,
+
.check_processor_compatibility = vmx_check_processor_compat,

.hardware_unsetup = vmx_hardware_unsetup,
@@ -8608,41 +8631,10 @@ static struct kvm_x86_init_ops vmx_init_ops __initdata = {
.pmu_ops = &intel_pmu_ops,
};

-static void vmx_cleanup_l1d_flush(void)
-{
- if (vmx_l1d_flush_pages) {
- free_pages((unsigned long)vmx_l1d_flush_pages, L1D_CACHE_ORDER);
- vmx_l1d_flush_pages = NULL;
- }
- /* Restore state so sysfs ignores VMX */
- l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO;
-}
-
-static void __vmx_exit(void)
-{
- allow_smaller_maxphyaddr = false;
-
- cpu_emergency_unregister_virt_callback(vmx_emergency_disable);
-
- 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.
@@ -8691,6 +8683,7 @@ static int __init vmx_init(void)
if (r)
goto err_kvm_init;

+
return 0;

err_kvm_init:
@@ -8699,4 +8692,3 @@ static int __init vmx_init(void)
kvm_x86_vendor_exit();
return r;
}
-module_init(vmx_init);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6b7f89fd2d47..e62daa2c3017 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -15,6 +15,7 @@
* Amit Shah <amit.shah@xxxxxxxxxxxx>
* Ben-Ami Yassour <benami@xxxxxxxxxx>
*/
+#include <asm-generic/errno.h>
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kvm_host.h>
@@ -13678,15 +13679,22 @@ static int __init kvm_x86_init(void)
{
kvm_mmu_x86_module_init();
mitigate_smt_rsb &= boot_cpu_has_bug(X86_BUG_SMT_RSB) && cpu_smt_possible();
- return 0;
+
+ if (kvm_is_svm_supported())
+ return svm_init();
+ else if (kvm_is_vmx_supported())
+ return vmx_init();
+
+ pr_err_ratelimited("kvm: no hardware support for SVM or VMX\n");
+ return -EOPNOTSUPP;
}
module_init(kvm_x86_init);

static void __exit kvm_x86_exit(void)
{
- /*
- * If module_init() is implemented, module_exit() must also be
- * implemented to allow module unload.
- */
+ kvm_exit();
+ kvm_x86_vendor_exit();
+ kvm_x86_ops.vendor_exit();
+
}
module_exit(kvm_x86_exit);
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 6b5490319d1b..322be05e6c5b 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -9,6 +9,21 @@
#include "kvm_cache_regs.h"
#include "kvm_emulate.h"

+#ifdef CONFIG_KVM_AMD
+bool kvm_is_svm_supported(void);
+int __init svm_init(void);
+void svm_module_exit(void);
+#else
+bool kvm_is_svm_supported(void) { return false; }
+#endif
+#ifdef CONFIG_KVM_INTEL
+bool kvm_is_vmx_supported(void);
+int __init vmx_init(void);
+void vmx_module_exit(void);
+#else
+bool kvm_is_vmx_supported(void) { return false; }
+#endif
+
struct kvm_caps {
/* control of guest tsc rate supported? */
bool has_tsc_control;
--
2.42.0.869.gea05f2083d-goog