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Message-Id: <20230608123448.71861-1-kconsul@linux.vnet.ibm.com>
Date: Thu, 8 Jun 2023 08:34:48 -0400
From: Kautuk Consul <kconsul@...ux.vnet.ibm.com>
To: Nicholas Piggin <npiggin@...il.com>,
Fabiano Rosas <farosas@...ux.ibm.com>, jpn@...ux.vnet.ibm.com,
Michael Ellerman <mpe@...erman.id.au>,
Paul Mackerras <paulus@...abs.org>,
Thomas Huth <thuth@...hat.com>,
Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org, linux-doc@...r.kernel.org,
Kautuk Consul <kconsul@...ux.vnet.ibm.com>
Subject: [PATCH] KVM: ppc64: Enable ring-based dirty memory tracking
- Enable CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL as ppc64 is weakly
ordered.
- Enable CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP because the
kvmppc_xive_native_set_attr is called in the context of an ioctl
syscall and will call kvmppc_xive_native_eq_sync for setting the
KVM_DEV_XIVE_EQ_SYNC attribute which will call mark_dirty_page()
when there isn't a running vcpu. Implemented the
kvm_arch_allow_write_without_running_vcpu to always return true
to allow mark_page_dirty_in_slot to mark the page dirty in the
memslot->dirty_bitmap in this case.
- Set KVM_DIRTY_LOG_PAGE_OFFSET for the ring buffer's physical page
offset.
- Implement the kvm_arch_mmu_enable_log_dirty_pt_masked function required
for the generic KVM code to call.
- Add a check to kvmppc_vcpu_run_hv for checking whether the dirty
ring is soft full.
- Implement the kvm_arch_flush_remote_tlbs_memslot function to support
the CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT config option.
On testing with live migration it was found that there is around
150-180 ms improvment in overall migration time with this patch.
Signed-off-by: Kautuk Consul <kconsul@...ux.vnet.ibm.com>
---
Documentation/virt/kvm/api.rst | 2 +-
arch/powerpc/include/uapi/asm/kvm.h | 2 ++
arch/powerpc/kvm/Kconfig | 2 ++
arch/powerpc/kvm/book3s_64_mmu_hv.c | 42 +++++++++++++++++++++++++++++
arch/powerpc/kvm/book3s_hv.c | 3 +++
include/linux/kvm_dirty_ring.h | 5 ++++
6 files changed, 55 insertions(+), 1 deletion(-)
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index add067793b90..ce1ebc513bae 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -8114,7 +8114,7 @@ regardless of what has actually been exposed through the CPUID leaf.
8.29 KVM_CAP_DIRTY_LOG_RING/KVM_CAP_DIRTY_LOG_RING_ACQ_REL
----------------------------------------------------------
-:Architectures: x86, arm64
+:Architectures: x86, arm64, ppc64
:Parameters: args[0] - size of the dirty log ring
KVM is capable of tracking dirty memory using ring buffers that are
diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
index 9f18fa090f1f..f722309ed7fb 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -33,6 +33,8 @@
/* Not always available, but if it is, this is the correct offset. */
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
+#define KVM_DIRTY_LOG_PAGE_OFFSET 64
+
struct kvm_regs {
__u64 pc;
__u64 cr;
diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index 902611954200..c93354ec3bd5 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -26,6 +26,8 @@ config KVM
select IRQ_BYPASS_MANAGER
select HAVE_KVM_IRQ_BYPASS
select INTERVAL_TREE
+ select HAVE_KVM_DIRTY_RING_ACQ_REL
+ select NEED_KVM_DIRTY_RING_WITH_BITMAP
config KVM_BOOK3S_HANDLER
bool
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 7f765d5ad436..c92e8022e017 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -2147,3 +2147,45 @@ void kvmppc_mmu_book3s_hv_init(struct kvm_vcpu *vcpu)
vcpu->arch.hflags |= BOOK3S_HFLAG_SLB;
}
+
+/*
+ * kvm_arch_mmu_enable_log_dirty_pt_masked - enable dirty logging for selected
+ * dirty pages.
+ *
+ * It write protects selected pages to enable dirty logging for them.
+ */
+void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
+ struct kvm_memory_slot *slot,
+ gfn_t gfn_offset,
+ unsigned long mask)
+{
+ phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
+ phys_addr_t start = (base_gfn + __ffs(mask)) << PAGE_SHIFT;
+ phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT;
+
+ while (start < end) {
+ pte_t *ptep;
+ unsigned int shift;
+
+ ptep = find_kvm_secondary_pte(kvm, start, &shift);
+
+ *ptep = __pte(pte_val(*ptep) & ~(_PAGE_WRITE));
+
+ start += PAGE_SIZE;
+ }
+}
+
+#ifdef CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP
+bool kvm_arch_allow_write_without_running_vcpu(struct kvm *kvm)
+{
+ return true;
+}
+#endif
+
+#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
+void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
+ const struct kvm_memory_slot *memslot)
+{
+ kvm_flush_remote_tlbs(kvm);
+}
+#endif
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 130bafdb1430..1d1264ea72c4 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4804,6 +4804,9 @@ static int kvmppc_vcpu_run_hv(struct kvm_vcpu *vcpu)
return -EINTR;
}
+ if (kvm_dirty_ring_check_request(vcpu))
+ return 0;
+
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
/*
* Don't allow entry with a suspended transaction, because
diff --git a/include/linux/kvm_dirty_ring.h b/include/linux/kvm_dirty_ring.h
index 4862c98d80d3..a00301059da5 100644
--- a/include/linux/kvm_dirty_ring.h
+++ b/include/linux/kvm_dirty_ring.h
@@ -69,6 +69,11 @@ static inline void kvm_dirty_ring_free(struct kvm_dirty_ring *ring)
{
}
+static inline bool kvm_dirty_ring_check_request(struct kvm_vcpu *vcpu)
+{
+ return false;
+}
+
#else /* CONFIG_HAVE_KVM_DIRTY_RING */
int kvm_cpu_dirty_log_size(void);
--
2.39.2
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