[PATCH 6/9] KVM: VMX: Use the kernel's version of VMXOFF

From: Sean Christopherson
Date: Wed Dec 30 2020 - 19:29:36 EST


Drop kvm_cpu_vmxoff() in favor of the kernel's cpu_vmxoff(). Modify the
latter to return -EIO on fault so that KVM can invoke
kvm_spurious_fault() when appropriate. In addition to the obvious code
reuse, dropping kvm_cpu_vmxoff() also eliminates VMX's last usage of the
__ex()/__kvm_handle_fault_on_reboot() macros, thus helping pave the way
toward dropping them entirely.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/include/asm/virtext.h | 7 ++++++-
arch/x86/kvm/vmx/vmx.c | 15 +++------------
2 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h
index 2cc585467667..8757078d4442 100644
--- a/arch/x86/include/asm/virtext.h
+++ b/arch/x86/include/asm/virtext.h
@@ -41,13 +41,18 @@ static inline int cpu_has_vmx(void)
* faults are guaranteed to be due to the !post-VMXON check unless the CPU is
* magically in RM, VM86, compat mode, or at CPL>0.
*/
-static inline void cpu_vmxoff(void)
+static inline int cpu_vmxoff(void)
{
asm_volatile_goto("1: vmxoff\n\t"
_ASM_EXTABLE(1b, %l[fault])
::: "cc", "memory" : fault);
+
+ cr4_clear_bits(X86_CR4_VMXE);
+ return 0;
+
fault:
cr4_clear_bits(X86_CR4_VMXE);
+ return -EIO;
}

static inline int cpu_vmx_enabled(void)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 131f390ade24..1a3b508ba8c1 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2321,21 +2321,12 @@ static void vmclear_local_loaded_vmcss(void)
__loaded_vmcs_clear(v);
}

-
-/* Just like cpu_vmxoff(), but with the __kvm_handle_fault_on_reboot()
- * tricks.
- */
-static void kvm_cpu_vmxoff(void)
-{
- asm volatile (__ex("vmxoff"));
-
- cr4_clear_bits(X86_CR4_VMXE);
-}
-
static void hardware_disable(void)
{
vmclear_local_loaded_vmcss();
- kvm_cpu_vmxoff();
+
+ if (cpu_vmxoff())
+ kvm_spurious_fault();

intel_pt_handle_vmx(0);
}
--
2.29.2.729.g45daf8777d-goog