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From: Yuan Yao <yuan.yao@linux.intel.com>
To: pbonzini@redhat.com
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, dgilbert@redhat.com,
	ehabkost@redhat.com, mst@redhat.com, armbru@redhat.com,
	mtosatti@redhat.com, ashish.kalra@amd.com,
	Thomas.Lendacky@amd.com, brijesh.singh@amd.com,
	isaku.yamahata@intel.com, yuan.yao@intel.com
Subject: [RFC][PATCH v1 02/10] Currently, guest memory access for debugging purposes is performed using memcpy(). Extend the 'struct MemoryRegion' to include new callbacks that can be used to override the use of memcpy() with something else.
Date: Thu,  6 May 2021 09:40:29 +0800	[thread overview]
Message-ID: <20210506014037.11982-3-yuan.yao@linux.intel.com> (raw)
In-Reply-To: <20210506014037.11982-1-yuan.yao@linux.intel.com>

From: Brijesh Singh <brijesh.singh@amd.com>

The new callbacks can be used to display the guest memory of an SEV guest
by registering callbacks to the SEV memory encryption/decryption APIs.

Typical usage:

mem_read(uint8_t *dest,
         const uint8_t *hva_src, hwaddr gpa_src,
         uint32_t len, MemTxAttrs attrs);
mem_write(uint8_t *hva_dest, hwaddr gpa_des,
          const uint8_t *src, uint32_t len, MemTxAttrs attrs);

MemoryRegionRAMReadWriteOps ops;
ops.read = mem_read;
ops.write = mem_write;

memory_region_init_ram(mem, NULL, "memory", size, NULL);
memory_region_set_ram_debug_ops(mem, ops);

Yuan Yao:
 - Add the gpa_src/gpa_des for read/write interface

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Yuan Yao <yuan.yao@intel.com>

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 5728a681b2..7e6fdcb8e4 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -444,6 +444,19 @@ struct IOMMUMemoryRegionClass {
 typedef struct CoalescedMemoryRange CoalescedMemoryRange;
 typedef struct MemoryRegionIoeventfd MemoryRegionIoeventfd;
 
+/* Memory Region RAM debug callback */
+typedef struct MemoryRegionRAMReadWriteOps MemoryRegionRAMReadWriteOps;
+
+struct MemoryRegionRAMReadWriteOps {
+    /* Write data into guest memory */
+    int (*write) (uint8_t *hva_dest, hwaddr gpa_des,
+                  const uint8_t *src, uint32_t len, MemTxAttrs attrs);
+    /* Read data from guest memory */
+    int (*read) (uint8_t *dest,
+                 const uint8_t *hva_src, hwaddr gpa_src,
+                 uint32_t len, MemTxAttrs attrs);
+};
+
 /** MemoryRegion:
  *
  * A struct representing a memory region.
@@ -487,6 +500,7 @@ struct MemoryRegion {
     const char *name;
     unsigned ioeventfd_nb;
     MemoryRegionIoeventfd *ioeventfds;
+    const MemoryRegionRAMReadWriteOps *ram_debug_ops;
 };
 
 struct IOMMUMemoryRegion {
@@ -1130,6 +1144,20 @@ void memory_region_init_rom_nomigrate(MemoryRegion *mr,
                                       uint64_t size,
                                       Error **errp);
 
+/**
+ * memory_region_set_ram_debug_ops: Set access ops for a give memory region.
+ *
+ * @mr: the #MemoryRegion to be initialized
+ * @ops: a function that will be used when accessing @target region during
+ *       debug
+ */
+static inline void
+memory_region_set_ram_debug_ops(MemoryRegion *mr,
+                                const MemoryRegionRAMReadWriteOps *ops)
+{
+    mr->ram_debug_ops = ops;
+}
+
 /**
  * memory_region_init_rom_device_nomigrate:  Initialize a ROM memory region.
  *                                 Writes are handled via callbacks.
-- 
2.20.1


  parent reply	other threads:[~2021-05-06  1:41 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-06  1:40 [RFC][PATCH v1 00/10] Enable encrypted guest memory access in QEMU Yuan Yao
2021-05-06  1:40 ` [RFC][PATCH v1 01/10] Extend the MemTxAttrs to include a 'debug' flag. The flag can be used as general indicator that operation was triggered by the debugger Yuan Yao
2021-05-06  1:40 ` Yuan Yao [this message]
2021-05-06  1:40 ` [RFC][PATCH v1 03/10] Introduce new interface KVMState::set_mr_debug_ops and its wrapper Yuan Yao
2021-05-06  1:40 ` [RFC][PATCH v1 04/10] Implements the common MemoryRegion::ram_debug_ops for encrypted guests Yuan Yao
2021-05-06  1:40 ` [RFC][PATCH v1 05/10] Set the RAM's MemoryRegion::debug_ops for INTEL TD guests Yuan Yao
2021-05-06  1:40 ` [RFC][PATCH v1 06/10] Introduce new MemoryDebugOps which hook into guest virtual and physical memory debug interfaces such as cpu_memory_rw_debug, to allow vendor specific assist/hooks for debugging and delegating accessing the guest memory. This is required for example in case of AMD SEV platform where the guest memory is encrypted and a SEV specific debug assist/hook will be required to access the guest memory Yuan Yao
2021-05-06  1:40 ` [RFC][PATCH v1 07/10] Add new address_space_read and address_space_write debug helper interfaces which can be invoked by vendor specific guest memory debug assist/hooks to do guest RAM memory accesses using the added MemoryRegion callbacks Yuan Yao
2021-05-06  1:40 ` [RFC][PATCH v1 08/10] Introduce debug version of physical memory read/write API Yuan Yao
2021-05-06  1:40 ` [RFC][PATCH v1 09/10] Change the monitor and other commands and gdbstub to use the debug API Yuan Yao
2021-05-06  1:40 ` [RFC][PATCH v1 10/10] Introduce new CPUClass::get_phys_page_attrs_debug implementation for encrypted guests Yuan Yao
2021-09-02 14:04 ` [RFC][PATCH v1 00/10] Enable encrypted guest memory access in QEMU Ashish Kalra
2021-09-02 23:23   ` Yao, Yuan
2021-09-07 10:51     ` Ashish Kalra

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