On 6/3/2023 12:19 AM, Anish Moorthy wrote:
Implement KVM_CAP_MEMORY_FAULT_INFO for efaults generated by
kvm_handle_error_pfn().
Signed-off-by: Anish Moorthy <amoorthy@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index c8961f45e3b1..cb71aae9aaec 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3291,6 +3291,10 @@ static void kvm_send_hwpoison_signal(struct kvm_memory_slot *slot, gfn_t gfn)
static int kvm_handle_error_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
{
+ uint64_t rounded_gfn;
+ uint64_t fault_size;
+ uint64_t fault_flags;
+
if (is_sigpending_pfn(fault->pfn)) {
kvm_handle_signal_exit(vcpu);
return -EINTR;
@@ -3309,6 +3313,15 @@ static int kvm_handle_error_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fa
return RET_PF_RETRY;
}
+ fault_size = KVM_HPAGE_SIZE(fault->goal_level);
IIUC, here fault->goal_level is always PG_LEVEL_4K.
goal_level could be adjusted in later kvm_tdp_mmu_map() -->
kvm_mmu_hugepage_adjust(), if kvm_faultin_pfn() doesn't fail, that is to say,
code path doesn't go through here.
I wonder, if you would like put (kind of) kvm_mmu_hugepage_adjust() here as
well, reporting to user space the maximum map size it could do with, OR, just
report 4K size, let user space itself to detect/decide max possible size (but
now I've no idea how to).
+ rounded_gfn = round_down(fault->gfn * PAGE_SIZE, fault_size);
+
+ fault_flags = 0;
+ if (fault->write)
+ fault_flags |= KVM_MEMORY_FAULT_FLAG_WRITE;
+ if (fault->exec)
+ fault_flags |= KVM_MEMORY_FAULT_FLAG_EXEC;
+ kvm_populate_efault_info(vcpu, rounded_gfn, fault_size, fault_flags);
return -EFAULT;
}
