Re: [PATCH] hw/loongarch: Add VM mode in IOCSR feature register in kvm mode

[gaosong]

在 2024/5/14 上午10:51, Bibo Mao 写道:

If VM runs in kvm mode, VM mode is added in IOCSR feature register.
So guest can detect kvm hypervisor type and enable possible pv functions.

Signed-off-by: Bibo Mao <maob...@loongson.cn>
---

Reviewed-by: Song Gao <gaos...@loongson.cn>

Thanks.
Song Gao

  hw/loongarch/virt.c | 12 +++++++++---
  1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/hw/loongarch/virt.c b/hw/loongarch/virt.c
index d87d9be576..44bcf25aee 100644
--- a/hw/loongarch/virt.c
+++ b/hw/loongarch/virt.c
@@ -10,6 +10,7 @@
  #include "qapi/error.h"
  #include "hw/boards.h"
  #include "hw/char/serial.h"
+#include "sysemu/kvm.h"
  #include "sysemu/sysemu.h"
  #include "sysemu/qtest.h"
  #include "sysemu/runstate.h"
@@ -840,18 +841,23 @@ static void virt_iocsr_misc_write(void *opaque, hwaddr 
addr,

static uint64_t virt_iocsr_misc_read(void *opaque, hwaddr addr, unsigned size)

  {
+    uint64_t ret;
+
      switch (addr) {
      case VERSION_REG:
          return 0x11ULL;
      case FEATURE_REG:
-        return 1ULL << IOCSRF_MSI | 1ULL << IOCSRF_EXTIOI |
-               1ULL << IOCSRF_CSRIPI;
+        ret = BIT(IOCSRF_MSI) | BIT(IOCSRF_EXTIOI) | BIT(IOCSRF_CSRIPI);
+        if (kvm_enabled()) {
+            ret |= BIT(IOCSRF_VM);
+        }
+        return ret;
      case VENDOR_REG:
          return 0x6e6f73676e6f6f4cULL; /* "Loongson" */
      case CPUNAME_REG:
          return 0x303030354133ULL;     /* "3A5000" */
      case MISC_FUNC_REG:
-        return 1ULL << IOCSRM_EXTIOI_EN;
+        return BIT_ULL(IOCSRM_EXTIOI_EN);
      }
      return 0ULL;
  }