On Mon, 31 Jul 2023 19:01:53 +0100,
Raghavendra Rao Ananta [off-list ref] wrote:

On Thu, Jul 27, 2023 at 6:01 AM Marc Zyngier [off-list ref] wrote:

quoted

On Thu, 27 Jul 2023 13:47:06 +0100,
Marc Zyngier [off-list ref] wrote:

quoted

On Sat, 22 Jul 2023 03:22:47 +0100,
Raghavendra Rao Ananta [off-list ref] wrote:

quoted

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*?

Ah, actually, nothing too bad would happen, as we convert the
kvm_call_hyp() into a function call.

But still, we don't need two copies of this stuff, and it can live in
mmu.c.

But since we have a couple of references in pgtable.c to
kvm_tlb_flush_vmid_range(), wouldn't that be an (linking) issue if we
moved the definition to mmu.c?

ld: error: undefined symbol: __kvm_nvhe_kvm_tlb_flush_vmid_range

quoted

quoted

quoted

referenced by pgtable.c:1148 (./arch/arm64/kvm/hyp/nvhe/../pgtable.c:1148)
              arch/arm64/kvm/hyp/nvhe/kvm_nvhe.o:(__kvm_nvhe_kvm_pgtable_stage2_unmap) in archive vmlinux.a

...

Ah crap, I missed that. What a mess. Forget it then. It really is a
shame that all the neat separation between mmu.c and pgtable.c that we
were aiming for is ultimately lost.

	M.

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

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