linux-kernel - [PATCH v10 056/108] KVM: TDX: don't request KVM_REQ_APIC_PAGE

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Message-Id: <f0f134dcf59f901e4b8960c7b3f242dcd42b1c40.1667110240.git.isaku.yamahata@intel.com>
Date:   Sat, 29 Oct 2022 23:22:57 -0700
From:   isaku.yamahata@...el.com
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     isaku.yamahata@...el.com, isaku.yamahata@...il.com,
        Paolo Bonzini <pbonzini@...hat.com>, erdemaktas@...gle.com,
        Sean Christopherson <seanjc@...gle.com>,
        Sagi Shahar <sagis@...gle.com>,
        David Matlack <dmatlack@...gle.com>
Subject: [PATCH v10 056/108] KVM: TDX: don't request KVM_REQ_APIC_PAGE_RELOAD

From: Isaku Yamahata <isaku.yamahata@...el.com>

TDX doesn't need APIC page depending on vapic and its callback is
WARN_ON_ONCE(is_tdx).  To avoid unnecessary overhead and WARN_ON_ONCE(),
skip requesting KVM_REQ_APIC_PAGE_RELOAD when TD.

  WARNING: arch/x86/kvm/vmx/main.c:696 vt_set_apic_access_page_addr+0x3c/0x50 [kvm_intel]
  RIP: 0010:vt_set_apic_access_page_addr+0x3c/0x50 [kvm_intel]
  Call Trace:
   vcpu_enter_guest+0x145d/0x24d0 [kvm]
   kvm_arch_vcpu_ioctl_run+0x25d/0xcc0 [kvm]
   kvm_vcpu_ioctl+0x414/0xa30 [kvm]
   __x64_sys_ioctl+0xc0/0x100
   do_syscall_64+0x39/0xc0
   entry_SYSCALL_64_after_hwframe+0x44/0xae

Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
---
 arch/x86/kvm/x86.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3868605462ed..5dadd0f9a10e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10487,7 +10487,9 @@ void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
 	 * Update it when it becomes invalid.
 	 */
 	apic_address = gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT);
-	if (start <= apic_address && apic_address < end)
+	/* TDX doesn't need APIC page. */
+	if (kvm->arch.vm_type != KVM_X86_TDX_VM &&
+	    start <= apic_address && apic_address < end)
 		kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
 }
 
-- 
2.25.1