qemu/target-i386-csv-Release-CSV3-shared-pages-after-unma.patch

From ee97f42ea46a2527d19a3e87f33994d350959a90 Mon Sep 17 00:00:00 2001
From: eastmoutain <14304864+eastmoutain@user.noreply.gitee.com>
Date: Mon, 20 May 2024 21:12:23 +0800
Subject: [PATCH] target/i386: csv: Release CSV3 shared pages after unmapping
 DMA

The shared pages are created for Device DMA access, release them
once DMA mapping is removed.

Signed-off-by: yangwencheng <yangwencheng@hygon.cn>
Signed-off-by: hanliyang <hanliyang@hygon.cn>
---
 linux-headers/linux/kvm.h     |  9 +++++++++
 target/i386/csv-sysemu-stub.c |  5 +++++
 target/i386/csv.c             | 34 ++++++++++++++++++++++++++++++++++
 target/i386/csv.h             |  1 +
 target/i386/kvm/kvm.c         |  1 +
 5 files changed, 50 insertions(+)

diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index 44a326fddc..a19683f1e9 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -2142,6 +2142,7 @@ enum csv3_cmd_id {
 	KVM_CSV3_SEND_ENCRYPT_CONTEXT,
 	KVM_CSV3_RECEIVE_ENCRYPT_DATA,
 	KVM_CSV3_RECEIVE_ENCRYPT_CONTEXT,
+	KVM_CSV3_HANDLE_MEMORY,
 
 	KVM_CSV3_SET_GUEST_PRIVATE_MEMORY = 0xc8,
 
@@ -2190,6 +2191,14 @@ struct kvm_csv3_receive_encrypt_context {
 	__u32 trans_len;
 };
 
+#define KVM_CSV3_RELEASE_SHARED_MEMORY (0x0001)
+
+struct kvm_csv3_handle_memory {
+	__u64 gpa;
+	__u32 num_pages;
+	__u32 opcode;
+};
+
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
 #define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)
 #define KVM_DEV_ASSIGN_MASK_INTX	(1 << 2)
diff --git a/target/i386/csv-sysemu-stub.c b/target/i386/csv-sysemu-stub.c
index e49755da5c..735cce0e4b 100644
--- a/target/i386/csv-sysemu-stub.c
+++ b/target/i386/csv-sysemu-stub.c
@@ -40,6 +40,11 @@ void csv3_shared_region_dma_unmap(uint64_t start, uint64_t end)
 
 }
 
+void csv3_shared_region_release(uint64_t gpa, uint32_t num_pages)
+{
+
+}
+
 int csv3_set_guest_private_memory(Error **errp)
 {
     g_assert_not_reached();
diff --git a/target/i386/csv.c b/target/i386/csv.c
index d9b50040a3..b229f7c317 100644
--- a/target/i386/csv.c
+++ b/target/i386/csv.c
@@ -270,6 +270,40 @@ end:
     return ret;
 }
 
+void csv3_shared_region_release(uint64_t gpa, uint32_t num_pages)
+{
+    struct kvm_csv3_handle_memory mem = { 0 };
+    MemoryRegion *mr = NULL;
+    void *hva;
+    int ret;
+
+    if (!csv3_enabled())
+        return;
+
+    if (!gpa || !num_pages)
+        return;
+
+    mem.gpa = (__u64)gpa;
+    mem.num_pages = (__u32)num_pages;
+    mem.opcode = (__u32)KVM_CSV3_RELEASE_SHARED_MEMORY;
+
+    /* unpin the pages */
+    ret = csv3_ioctl(KVM_CSV3_HANDLE_MEMORY, &mem, NULL);
+    if (ret <= 0) {
+        if (ret < 0)
+            error_report("%s: CSV3 unpin failed ret %d", __func__, ret);
+        return;
+    }
+
+    /* drop the pages */
+    hva = gpa2hva(&mr, gpa, num_pages << TARGET_PAGE_BITS, NULL);
+    if (hva) {
+        ret = madvise(hva, num_pages << TARGET_PAGE_BITS, MADV_DONTNEED);
+        if (ret)
+            error_report("%s: madvise failed %d", __func__, ret);
+    }
+}
+
 void csv3_shared_region_dma_unmap(uint64_t start, uint64_t end)
 {
     MemoryRegionSection section;
diff --git a/target/i386/csv.h b/target/i386/csv.h
index fb669279a8..70f9933d3b 100644
--- a/target/i386/csv.h
+++ b/target/i386/csv.h
@@ -124,6 +124,7 @@ int csv3_load_data(uint64_t gpa, uint8_t *ptr, uint64_t len, Error **errp);
 
 int csv3_shared_region_dma_map(uint64_t start, uint64_t end);
 void csv3_shared_region_dma_unmap(uint64_t start, uint64_t end);
+void csv3_shared_region_release(uint64_t gpa, uint32_t num_pages);
 int csv3_load_incoming_page(QEMUFile *f, uint8_t *ptr);
 int csv3_load_incoming_context(QEMUFile *f);
 int csv3_queue_outgoing_page(uint8_t *ptr, uint32_t sz, uint64_t addr);
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index a867512822..2df3ff99c3 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -5099,6 +5099,7 @@ static int kvm_handle_exit_hypercall(X86CPU *cpu, struct kvm_run *run)
         if (enc) {
             sev_remove_shared_regions_list(gfn_start, gfn_end);
             csv3_shared_region_dma_unmap(gpa, gfn_end << TARGET_PAGE_BITS);
+            csv3_shared_region_release(gpa, npages);
          } else {
             sev_add_shared_regions_list(gfn_start, gfn_end);
             csv3_shared_region_dma_map(gpa, gfn_end << TARGET_PAGE_BITS);
-- 
2.41.0.windows.1