On Tue, Aug 3, 2021 at 6:49 PM limingwang (A) [off-list ref] wrote:

quoted

diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c index

fa9a4f9b9542..4b294113c63b 100644

--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c

@@ -300,7 +300,8 @@ static void stage2_op_pte(struct kvm *kvm, gpa_t

addr,
      }
 }

-static void stage2_unmap_range(struct kvm *kvm, gpa_t start, gpa_t size)
+static void stage2_unmap_range(struct kvm *kvm, gpa_t start,
+                            gpa_t size, bool may_block)
 {
      int ret;
      pte_t *ptep;

@@ -325,6 +326,13 @@ static void stage2_unmap_range(struct kvm *kvm,

gpa_t start, gpa_t size)

 next:
              addr += page_size;
+
+             /*
+              * If the range is too large, release the kvm->mmu_lock
+              * to prevent starvation and lockup detector warnings.
+              */
+             if (may_block && addr < end)
+                     cond_resched_lock(&kvm->mmu_lock);
      }
 }

@@ -405,7 +413,6 @@ static int stage2_ioremap(struct kvm *kvm, gpa_t gpa,

phys_addr_t hpa,
 out:
      stage2_cache_flush(&pcache);
      return ret;
-
 }

 void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm, @@
-547,7 +554,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
      spin_lock(&kvm->mmu_lock);
      if (ret)
              stage2_unmap_range(kvm, mem->guest_phys_addr,
-                                mem->memory_size);
+                                mem->memory_size, false);
      spin_unlock(&kvm->mmu_lock);

 out:

@@ -555,6 +562,73 @@ int kvm_arch_prepare_memory_region(struct kvm

*kvm,
      return ret;
 }

+bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+     if (!kvm->arch.pgd)
+             return 0;
+
+     stage2_unmap_range(kvm, range->start << PAGE_SHIFT,
+                        (range->end - range->start) << PAGE_SHIFT,
+                        range->may_block);
+     return 0;
+}
+
+bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range) {
+     int ret;
+     kvm_pfn_t pfn = pte_pfn(range->pte);
+
+     if (!kvm->arch.pgd)
+             return 0;
+
+     WARN_ON(range->end - range->start != 1);
+
+     ret = stage2_map_page(kvm, NULL, range->start << PAGE_SHIFT,
+                           __pfn_to_phys(pfn), PAGE_SIZE, true, true);
+     if (ret) {
+             kvm_err("Failed to map stage2 page (error %d)\n", ret);
+             return 1;
+     }

Hi, Anup

I think that it is not appropriate to add kvm_err here, because stage2_set_pte function
may apply for memory based on the pcache parameter. If the value of pcache is NULL,
stage2_set_pte function considers that there is not enough memory and here an invalid
error log is generated.

As an example, this error log is printed when a VM is migrating. But finally the VM migration
is successful. And if the kvm_err is added to the same position in the ARM architecture, the
same error log is also printed.

Okay, I have converted kvm_err() to kvm_debug(). In the future, we can totally
remove it as well.

Please try riscv_kvm_v20 branch at:
https://github.com/avpatel/linux.git

Regards,
Anup

Mingwang

quoted

+     return 0;
+}
+

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv