[PATCH 51/60] kvm: x86: Share pio_data across planes

[Jörg Rödel]

From: Joerg Roedel <joerg.roedel@xxxxxxx>

The vcpu->arch.pio_data pointer is memory mapped to user-space
alongside the kvm_run page. So it also needs to be common across all
planes for a given VCPU index.

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
 arch/x86/include/asm/kvm_host.h |  2 ++
 arch/x86/kvm/x86.c              | 20 +++++++++++---------
 virt/kvm/kvm_main.c             |  2 +-
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0327b77e56b7..1b7aa48c961e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -801,6 +801,8 @@ struct kvm_vcpu_arch_common {
 	bool cpuid_dynamic_bits_dirty;
 	bool is_amd_compatible;
 
+	void *pio_data;
+
 	/*
 	 * cpu_caps holds the effective guest capabilities, i.e. the features
 	 * the vCPU is allowed to use.  Typically, but not always, features can
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5f48392d4738..08fe65b8d57d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8532,7 +8532,7 @@ static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
 }
 
 static int emulator_pio_in(struct kvm_vcpu *vcpu, int size,
-      			   unsigned short port, void *val, unsigned int count)
+			   unsigned short port, void *val, unsigned int count)
 {
 	int r = emulator_pio_in_out(vcpu, size, port, val, count, true);
 	if (r)
@@ -12936,7 +12936,6 @@ int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
 
 int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 {
-	struct page *page;
 	int r;
 
 	vcpu->arch.last_vmentry_cpu = -1;
@@ -12960,10 +12959,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 
 	r = -ENOMEM;
 
-	page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
-	if (!page)
-		goto fail_free_lapic;
-	vcpu->arch.pio_data = page_address(page);
+	vcpu->arch.pio_data = vcpu->common->arch.pio_data;
 
 	vcpu->arch.mce_banks = kcalloc(KVM_MAX_MCE_BANKS * 4, sizeof(u64),
 				       GFP_KERNEL_ACCOUNT);
@@ -13023,8 +13019,6 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 fail_free_mce_banks:
 	kfree(vcpu->arch.mce_banks);
 	kfree(vcpu->arch.mci_ctl2_banks);
-	free_page((unsigned long)vcpu->arch.pio_data);
-fail_free_lapic:
 	kvm_free_lapic(vcpu);
 fail_mmu_destroy:
 	kvm_mmu_destroy(vcpu);
@@ -13072,16 +13066,24 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 	idx = srcu_read_lock(&vcpu->kvm->srcu);
 	kvm_mmu_destroy(vcpu);
 	srcu_read_unlock(&vcpu->kvm->srcu, idx);
-	free_page((unsigned long)vcpu->arch.pio_data);
 }
 
 int kvm_arch_vcpu_common_init(struct kvm_vcpu_common *common)
 {
+	struct page *page;
+
+	page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+	if (!page)
+		return -ENOMEM;
+
+	common->arch.pio_data = page_address(page);
+
 	return 0;
 }
 
 void kvm_arch_vcpu_common_destroy(struct kvm_vcpu_common *common)
 {
+	free_page((unsigned long)common->arch.pio_data);
 	kvfree(common->arch.cpuid_entries);
 }
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a6d7601c3412..8f1a16af519a 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4250,7 +4250,7 @@ static vm_fault_t kvm_vcpu_fault(struct vm_fault *vmf)
 		page = virt_to_page(vcpu->run);
 #ifdef CONFIG_X86
 	else if (vmf->pgoff == KVM_PIO_PAGE_OFFSET)
-		page = virt_to_page(vcpu->arch.pio_data);
+		page = virt_to_page(vcpu->common->arch.pio_data);
 #endif
 #ifdef CONFIG_KVM_MMIO
 	else if (vmf->pgoff == KVM_COALESCED_MMIO_PAGE_OFFSET)
-- 
2.53.0