Thread (51 messages) 51 messages, 4 authors, 2023-08-08

Re: [PATCH v7 08/12] KVM: arm64: Define kvm_tlb_flush_vmid_range()

From: Marc Zyngier <maz@kernel.org>
Date: 2023-07-27 12:47:19
Also in: kvm, kvm-riscv, kvmarm, linux-mips, linux-riscv, lkml

On Sat, 22 Jul 2023 03:22:47 +0100,
Raghavendra Rao Ananta [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Implement the helper kvm_tlb_flush_vmid_range() that acts
as a wrapper for range-based TLB invalidations. For the
given VMID, use the range-based TLBI instructions to do
the job or fallback to invalidating all the TLB entries.

Signed-off-by: Raghavendra Rao Ananta <redacted>
Reviewed-by: Gavin Shan <redacted>
Reviewed-by: Shaoqin Huang <redacted>
---
 arch/arm64/include/asm/kvm_pgtable.h | 10 ++++++++++
 arch/arm64/kvm/hyp/pgtable.c         | 20 ++++++++++++++++++++
 2 files changed, 30 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 8294a9a7e566..5e8b1ff07854 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -754,4 +754,14 @@ enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte);
  *	   kvm_pgtable_prot format.
  */
 enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte);
+
+/**
+ * kvm_tlb_flush_vmid_range() - Invalidate/flush a range of TLB entries
+ *
+ * @mmu:	Stage-2 KVM MMU struct
+ * @addr:	The base Intermediate physical address from which to invalidate
+ * @size:	Size of the range from the base to invalidate
+ */
+void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
+				phys_addr_t addr, size_t size);
 #endif	/* __ARM64_KVM_PGTABLE_H__ */
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index aa740a974e02..5d14d5d5819a 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -670,6 +670,26 @@ static bool stage2_has_fwb(struct kvm_pgtable *pgt)
 	return !(pgt->flags & KVM_PGTABLE_S2_NOFWB);
 }
 
+void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
+				phys_addr_t addr, size_t size)
+{
+	unsigned long pages, inval_pages;
+
+	if (!system_supports_tlb_range()) {
+		kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
+		return;
+	}
+
+	pages = size >> PAGE_SHIFT;
+	while (pages > 0) {
+		inval_pages = min(pages, MAX_TLBI_RANGE_PAGES);
+		kvm_call_hyp(__kvm_tlb_flush_vmid_range, mmu, addr, inval_pages);
+
+		addr += inval_pages << PAGE_SHIFT;
+		pages -= inval_pages;
+	}
+}
+
This really shouldn't live in pgtable.c. This code gets linked into
the EL2 object. What do you think happens if, for some reason, this
gets called *from EL2*?

Furthermore, this doesn't deal with page tables at all. Why isn't
mmu.c a convenient place for it, as an integral part of
kvm_arch_flush_remote_tlbs_range?

	M.

-- 
Without deviation from the norm, progress is not possible.

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