[PATCH v5 3/7] KVM: x86: hyper-v: Move the remote TLB flush logic out of vmx

From: Vineeth Pillai
Date: Thu Jun 03 2021 - 11:15:00 EST

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Currently the remote TLB flush logic is specific to VMX.
Move it to a common place so that SVM can use it as well.

Signed-off-by: Vineeth Pillai <viremana@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 9 +++
arch/x86/kvm/Makefile | 5 ++
arch/x86/kvm/kvm_onhyperv.c | 93 ++++++++++++++++++++++++++++
arch/x86/kvm/kvm_onhyperv.h | 32 ++++++++++
arch/x86/kvm/vmx/vmx.c | 105 +-------------------------------
arch/x86/kvm/vmx/vmx.h | 9 ---
arch/x86/kvm/x86.c | 9 +++
7 files changed, 150 insertions(+), 112 deletions(-)
create mode 100644 arch/x86/kvm/kvm_onhyperv.c
create mode 100644 arch/x86/kvm/kvm_onhyperv.h

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index cbbcee0a84f9..bab305230e8d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -849,6 +849,10 @@ struct kvm_vcpu_arch {

/* Protected Guests */
bool guest_state_protected;
+
+#if IS_ENABLED(CONFIG_HYPERV)
+ hpa_t hv_root_tdp;
+#endif
};

struct kvm_lpage_info {
@@ -1122,6 +1126,11 @@ struct kvm_arch {
*/
spinlock_t tdp_mmu_pages_lock;
#endif /* CONFIG_X86_64 */
+
+#if IS_ENABLED(CONFIG_HYPERV)
+ hpa_t hv_root_tdp;
+ spinlock_t hv_root_tdp_lock;
+#endif
};

struct kvm_vm_stat {
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index c589db5d91b3..a06745c2fef1 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -18,6 +18,11 @@ kvm-y += x86.o emulate.o i8259.o irq.o lapic.o \
i8254.o ioapic.o irq_comm.o cpuid.o pmu.o mtrr.o \
hyperv.o debugfs.o mmu/mmu.o mmu/page_track.o \
mmu/spte.o
+
+ifdef CONFIG_HYPERV
+kvm-y += kvm_onhyperv.o
+endif
+
kvm-$(CONFIG_X86_64) += mmu/tdp_iter.o mmu/tdp_mmu.o
kvm-$(CONFIG_KVM_XEN) += xen.o

diff --git a/arch/x86/kvm/kvm_onhyperv.c b/arch/x86/kvm/kvm_onhyperv.c
new file mode 100644
index 000000000000..c7db2df50a7a
--- /dev/null
+++ b/arch/x86/kvm/kvm_onhyperv.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * KVM L1 hypervisor optimizations on Hyper-V.
+ */
+
+#include <linux/kvm_host.h>
+#include <asm/mshyperv.h>
+
+#include "hyperv.h"
+#include "kvm_onhyperv.h"
+
+static int kvm_fill_hv_flush_list_func(struct hv_guest_mapping_flush_list *flush,
+ void *data)
+{
+ struct kvm_tlb_range *range = data;
+
+ return hyperv_fill_flush_guest_mapping_list(flush, range->start_gfn,
+ range->pages);
+}
+
+static inline int hv_remote_flush_root_tdp(hpa_t root_tdp,
+ struct kvm_tlb_range *range)
+{
+ if (range)
+ return hyperv_flush_guest_mapping_range(root_tdp,
+ kvm_fill_hv_flush_list_func, (void *)range);
+ else
+ return hyperv_flush_guest_mapping(root_tdp);
+}
+
+int hv_remote_flush_tlb_with_range(struct kvm *kvm,
+ struct kvm_tlb_range *range)
+{
+ struct kvm_arch *kvm_arch = &kvm->arch;
+ struct kvm_vcpu *vcpu;
+ int ret = 0, i, nr_unique_valid_roots;
+ hpa_t root;
+
+ spin_lock(&kvm_arch->hv_root_tdp_lock);
+
+ if (!VALID_PAGE(kvm_arch->hv_root_tdp)) {
+ nr_unique_valid_roots = 0;
+
+ /*
+ * Flush all valid roots, and see if all vCPUs have converged
+ * on a common root, in which case future flushes can skip the
+ * loop and flush the common root.
+ */
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ root = vcpu->arch.hv_root_tdp;
+ if (!VALID_PAGE(root) || root == kvm_arch->hv_root_tdp)
+ continue;
+
+ /*
+ * Set the tracked root to the first valid root. Keep
+ * this root for the entirety of the loop even if more
+ * roots are encountered as a low effort optimization
+ * to avoid flushing the same (first) root again.
+ */
+ if (++nr_unique_valid_roots == 1)
+ kvm_arch->hv_root_tdp = root;
+
+ if (!ret)
+ ret = hv_remote_flush_root_tdp(root, range);
+
+ /*
+ * Stop processing roots if a failure occurred and
+ * multiple valid roots have already been detected.
+ */
+ if (ret && nr_unique_valid_roots > 1)
+ break;
+ }
+
+ /*
+ * The optimized flush of a single root can't be used if there
+ * are multiple valid roots (obviously).
+ */
+ if (nr_unique_valid_roots > 1)
+ kvm_arch->hv_root_tdp = INVALID_PAGE;
+ } else {
+ ret = hv_remote_flush_root_tdp(kvm_arch->hv_root_tdp, range);
+ }
+
+ spin_unlock(&kvm_arch->hv_root_tdp_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(hv_remote_flush_tlb_with_range);
+
+int hv_remote_flush_tlb(struct kvm *kvm)
+{
+ return hv_remote_flush_tlb_with_range(kvm, NULL);
+}
+EXPORT_SYMBOL_GPL(hv_remote_flush_tlb);
diff --git a/arch/x86/kvm/kvm_onhyperv.h b/arch/x86/kvm/kvm_onhyperv.h
new file mode 100644
index 000000000000..c03f01024a70
--- /dev/null
+++ b/arch/x86/kvm/kvm_onhyperv.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * KVM L1 hypervisor optimizations on Hyper-V.
+ */
+
+#ifndef __ARCH_X86_KVM_KVM_ONHYPERV_H__
+#define __ARCH_X86_KVM_KVM_ONHYPERV_H__
+
+#if IS_ENABLED(CONFIG_HYPERV)
+int hv_remote_flush_tlb_with_range(struct kvm *kvm,
+ struct kvm_tlb_range *range);
+int hv_remote_flush_tlb(struct kvm *kvm);
+
+static inline void hv_track_root_tdp(struct kvm_vcpu *vcpu, hpa_t root_tdp)
+{
+ struct kvm_arch *kvm_arch = &vcpu->kvm->arch;
+
+ if (kvm_x86_ops.tlb_remote_flush == hv_remote_flush_tlb) {
+ spin_lock(&kvm_arch->hv_root_tdp_lock);
+ vcpu->arch.hv_root_tdp = root_tdp;
+ if (root_tdp != kvm_arch->hv_root_tdp)
+ kvm_arch->hv_root_tdp = INVALID_PAGE;
+ spin_unlock(&kvm_arch->hv_root_tdp_lock);
+ }
+}
+#else
+static inline void hv_track_root_tdp(struct kvm_vcpu *vcpu, hpa_t root_tdp)
+{
+}
+#endif
+#endif
+
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d000cddbd734..117fb88cd354 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -52,6 +52,7 @@
#include "cpuid.h"
#include "evmcs.h"
#include "hyperv.h"
+#include "kvm_onhyperv.h"
#include "irq.h"
#include "kvm_cache_regs.h"
#include "lapic.h"
@@ -474,86 +475,6 @@ static const u32 vmx_uret_msrs_list[] = {
static bool __read_mostly enlightened_vmcs = true;
module_param(enlightened_vmcs, bool, 0444);

-static int kvm_fill_hv_flush_list_func(struct hv_guest_mapping_flush_list *flush,
- void *data)
-{
- struct kvm_tlb_range *range = data;
-
- return hyperv_fill_flush_guest_mapping_list(flush, range->start_gfn,
- range->pages);
-}
-
-static inline int hv_remote_flush_root_ept(hpa_t root_ept,
- struct kvm_tlb_range *range)
-{
- if (range)
- return hyperv_flush_guest_mapping_range(root_ept,
- kvm_fill_hv_flush_list_func, (void *)range);
- else
- return hyperv_flush_guest_mapping(root_ept);
-}
-
-static int hv_remote_flush_tlb_with_range(struct kvm *kvm,
- struct kvm_tlb_range *range)
-{
- struct kvm_vmx *kvm_vmx = to_kvm_vmx(kvm);
- struct kvm_vcpu *vcpu;
- int ret = 0, i, nr_unique_valid_roots;
- hpa_t root;
-
- spin_lock(&kvm_vmx->hv_root_ept_lock);
-
- if (!VALID_PAGE(kvm_vmx->hv_root_ept)) {
- nr_unique_valid_roots = 0;
-
- /*
- * Flush all valid roots, and see if all vCPUs have converged
- * on a common root, in which case future flushes can skip the
- * loop and flush the common root.
- */
- kvm_for_each_vcpu(i, vcpu, kvm) {
- root = to_vmx(vcpu)->hv_root_ept;
- if (!VALID_PAGE(root) || root == kvm_vmx->hv_root_ept)
- continue;
-
- /*
- * Set the tracked root to the first valid root. Keep
- * this root for the entirety of the loop even if more
- * roots are encountered as a low effort optimization
- * to avoid flushing the same (first) root again.
- */
- if (++nr_unique_valid_roots == 1)
- kvm_vmx->hv_root_ept = root;
-
- if (!ret)
- ret = hv_remote_flush_root_ept(root, range);
-
- /*
- * Stop processing roots if a failure occurred and
- * multiple valid roots have already been detected.
- */
- if (ret && nr_unique_valid_roots > 1)
- break;
- }
-
- /*
- * The optimized flush of a single root can't be used if there
- * are multiple valid roots (obviously).
- */
- if (nr_unique_valid_roots > 1)
- kvm_vmx->hv_root_ept = INVALID_PAGE;
- } else {
- ret = hv_remote_flush_root_ept(kvm_vmx->hv_root_ept, range);
- }
-
- spin_unlock(&kvm_vmx->hv_root_ept_lock);
- return ret;
-}
-static int hv_remote_flush_tlb(struct kvm *kvm)
-{
- return hv_remote_flush_tlb_with_range(kvm, NULL);
-}
-
static int hv_enable_direct_tlbflush(struct kvm_vcpu *vcpu)
{
struct hv_enlightened_vmcs *evmcs;
@@ -581,21 +502,6 @@ static int hv_enable_direct_tlbflush(struct kvm_vcpu *vcpu)

#endif /* IS_ENABLED(CONFIG_HYPERV) */

-static void hv_track_root_ept(struct kvm_vcpu *vcpu, hpa_t root_ept)
-{
-#if IS_ENABLED(CONFIG_HYPERV)
- struct kvm_vmx *kvm_vmx = to_kvm_vmx(vcpu->kvm);
-
- if (kvm_x86_ops.tlb_remote_flush == hv_remote_flush_tlb) {
- spin_lock(&kvm_vmx->hv_root_ept_lock);
- to_vmx(vcpu)->hv_root_ept = root_ept;
- if (root_ept != kvm_vmx->hv_root_ept)
- kvm_vmx->hv_root_ept = INVALID_PAGE;
- spin_unlock(&kvm_vmx->hv_root_ept_lock);
- }
-#endif
-}
-
/*
* Comment's format: document - errata name - stepping - processor name.
* Refer from
@@ -3202,7 +3108,7 @@ static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa,
eptp = construct_eptp(vcpu, root_hpa, root_level);
vmcs_write64(EPT_POINTER, eptp);

- hv_track_root_ept(vcpu, root_hpa);
+ hv_track_root_tdp(vcpu, root_hpa);

if (!enable_unrestricted_guest && !is_paging(vcpu))
guest_cr3 = to_kvm_vmx(kvm)->ept_identity_map_addr;
@@ -6980,9 +6886,6 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu)
vmx->pi_desc.nv = POSTED_INTR_VECTOR;
vmx->pi_desc.sn = 1;

-#if IS_ENABLED(CONFIG_HYPERV)
- vmx->hv_root_ept = INVALID_PAGE;
-#endif
return 0;

free_vmcs:
@@ -6999,10 +6902,6 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu)

static int vmx_vm_init(struct kvm *kvm)
{
-#if IS_ENABLED(CONFIG_HYPERV)
- spin_lock_init(&to_kvm_vmx(kvm)->hv_root_ept_lock);
-#endif
-
if (!ple_gap)
kvm->arch.pause_in_guest = true;

diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 008cb87ff088..d1363e734a01 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -328,10 +328,6 @@ struct vcpu_vmx {
/* SGX Launch Control public key hash */
u64 msr_ia32_sgxlepubkeyhash[4];

-#if IS_ENABLED(CONFIG_HYPERV)
- u64 hv_root_ept;
-#endif
-
struct pt_desc pt_desc;
struct lbr_desc lbr_desc;

@@ -349,11 +345,6 @@ struct kvm_vmx {
unsigned int tss_addr;
bool ept_identity_pagetable_done;
gpa_t ept_identity_map_addr;
-
-#if IS_ENABLED(CONFIG_HYPERV)
- hpa_t hv_root_ept;
- spinlock_t hv_root_ept_lock;
-#endif
};

bool nested_vmx_allowed(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6eda2834fc05..580f3c6c86f9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10279,6 +10279,10 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
vcpu->arch.pending_external_vector = -1;
vcpu->arch.preempted_in_kernel = false;

+#if IS_ENABLED(CONFIG_HYPERV)
+ vcpu->arch.hv_root_tdp = INVALID_PAGE;
+#endif
+
r = static_call(kvm_x86_vcpu_create)(vcpu);
if (r)
goto free_guest_fpu;
@@ -10662,6 +10666,11 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)

kvm->arch.guest_can_read_msr_platform_info = true;

+#if IS_ENABLED(CONFIG_HYPERV)
+ spin_lock_init(&kvm->arch.hv_root_tdp_lock);
+ kvm->arch.hv_root_tdp = INVALID_PAGE;
+#endif
+
INIT_DELAYED_WORK(&kvm->arch.kvmclock_update_work, kvmclock_update_fn);
INIT_DELAYED_WORK(&kvm->arch.kvmclock_sync_work, kvmclock_sync_fn);

--
2.25.1

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