qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH] MIPS: remove support for trap and emulate KVM


From: Philippe Mathieu-Daudé
Subject: Re: [PATCH] MIPS: remove support for trap and emulate KVM
Date: Sun, 18 Dec 2022 14:35:12 +0100
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.5.1

On 18/12/22 01:06, Paolo Bonzini wrote:
This support was limited to the Malta board, drop it.
I do not have a machine that can run VZ KVM, so I am assuming
that it works for -M malta as well.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
  docs/about/deprecated.rst       |  9 -------
  docs/about/removed-features.rst |  9 +++++++
  hw/mips/malta.c                 | 44 ++++-----------------------------
  target/mips/cpu.c               |  7 +-----
  target/mips/cpu.h               |  2 --
  target/mips/kvm.c               | 11 +--------
  target/mips/sysemu/addr.c       | 17 -------------
  target/mips/sysemu/physaddr.c   | 13 ----------
  8 files changed, 16 insertions(+), 96 deletions(-)

diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 93affe3669ff..b28f50b22fa9 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -199,15 +199,6 @@ deprecated.  Use ``sections`` instead.
  Member ``section-size`` in return value elements with meta-type ``uint64`` is
  deprecated.  Use ``sections`` instead.
-System accelerators
--------------------
-
-MIPS ``Trap-and-Emul`` KVM support (since 6.0)
-''''''''''''''''''''''''''''''''''''''''''''''
-
-The MIPS ``Trap-and-Emul`` KVM host and guest support has been removed
-from Linux upstream kernel, declare it deprecated.
-
  Host Architectures
  ------------------
diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst
index 7e12145c120d..91c9dce6d6e0 100644
--- a/docs/about/removed-features.rst
+++ b/docs/about/removed-features.rst
@@ -616,6 +616,15 @@ x86 ``Icelake-Client`` CPU (removed in 7.1)
  There isn't ever Icelake Client CPU, it is some wrong and imaginary one.
  Use ``Icelake-Server`` instead.
+System accelerators
+-------------------
+
+MIPS "Trap-and-Emulate" KVM support (removed in 8.0)
+''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+The MIPS "Trap-and-Emulate" KVM host and guest support was removed
+from Linux in 2021, and is not supported anymore by QEMU either.
+
  System emulator machines
  ------------------------
diff --git a/hw/mips/malta.c b/hw/mips/malta.c
index c0a2e0ab041b..13b9b3bc6d93 100644
--- a/hw/mips/malta.c
+++ b/hw/mips/malta.c
@@ -1013,7 +1013,6 @@ static uint64_t load_kernel(void)
      uint32_t *prom_buf;
      long prom_size;
      int prom_index = 0;
-    uint64_t (*xlate_to_kseg0) (void *opaque, uint64_t addr);
      uint8_t rng_seed[32];
      char rng_seed_hex[sizeof(rng_seed) * 2 + 1];
      size_t rng_seed_prom_offset;
@@ -1037,19 +1036,9 @@ static uint64_t load_kernel(void)
      }
/* Check where the kernel has been linked */
-    if (kernel_entry & 0x80000000ll) {
-        if (kvm_enabled()) {
-            error_report("KVM guest kernels must be linked in useg. "
-                         "Did you forget to enable CONFIG_KVM_GUEST?");
-            exit(1);
-        }
-
-        xlate_to_kseg0 = cpu_mips_phys_to_kseg0;
-    } else {
-        /* if kernel entry is in useg it is probably a KVM T&E kernel */
-        mips_um_ksegs_enable();
-
-        xlate_to_kseg0 = cpu_mips_kvm_um_phys_to_kseg0;
+    if (!(kernel_entry & 0x80000000ll)) {
+        error_report("CONFIG_KVM_GUEST kernels are not supported");
+        exit(1);
      }
/* load initrd */
@@ -1090,7 +1079,7 @@ static uint64_t load_kernel(void)
      if (initrd_size > 0) {
          prom_set(prom_buf, prom_index++,
                   "rd_start=0x%" PRIx64 " rd_size=%" PRId64 " %s",
-                 xlate_to_kseg0(NULL, initrd_offset),
+                 cpu_mips_phys_to_kseg0(NULL, initrd_offset),
                   initrd_size, loaderparams.kernel_cmdline);
      } else {
          prom_set(prom_buf, prom_index++, "%s", loaderparams.kernel_cmdline);
@@ -1157,11 +1146,6 @@ static void main_cpu_reset(void *opaque)
      }
malta_mips_config(cpu);
-
-    if (kvm_enabled()) {
-        /* Start running from the bootloader we wrote to end of RAM */
-        env->active_tc.PC = 0x40000000 + loaderparams.ram_low_size;
-    }
  }
static void create_cpu_without_cps(MachineState *ms, MaltaState *s,
@@ -1295,13 +1279,7 @@ void mips_malta_init(MachineState *machine)
      fl_idx++;
      if (kernel_filename) {
          ram_low_size = MIN(ram_size, 256 * MiB);
-        /* For KVM we reserve 1MB of RAM for running bootloader */
-        if (kvm_enabled()) {
-            ram_low_size -= 0x100000;
-            bootloader_run_addr = cpu_mips_kvm_um_phys_to_kseg0(NULL, 
ram_low_size);
-        } else {
-            bootloader_run_addr = cpu_mips_phys_to_kseg0(NULL, RESET_ADDRESS);
-        }
+        bootloader_run_addr = cpu_mips_phys_to_kseg0(NULL, RESET_ADDRESS);
/* Write a small bootloader to the flash location. */
          loaderparams.ram_size = ram_size;
@@ -1318,20 +1296,8 @@ void mips_malta_init(MachineState *machine)
              write_bootloader_nanomips(memory_region_get_ram_ptr(bios),
                                        bootloader_run_addr, kernel_entry);
          }
-        if (kvm_enabled()) {
-            /* Write the bootloader code @ the end of RAM, 1MB reserved */
-            write_bootloader(memory_region_get_ram_ptr(ram_low_preio) +
-                                    ram_low_size,
-                             bootloader_run_addr, kernel_entry);
-        }
      } else {
          target_long bios_size = FLASH_SIZE;
-        /* The flash region isn't executable from a KVM guest */
-        if (kvm_enabled()) {
-            error_report("KVM enabled but no -kernel argument was specified. "
-                         "Booting from flash is not supported with KVM.");
-            exit(1);
-        }
          /* Load firmware from flash. */
          if (!dinfo) {
              /* Load a BIOS image. */
diff --git a/target/mips/cpu.c b/target/mips/cpu.c
index 7a565466cb3f..065a9cd10ec9 100644
--- a/target/mips/cpu.c
+++ b/target/mips/cpu.c
@@ -290,12 +290,7 @@ static void mips_cpu_reset(DeviceState *dev)
      env->tlb->tlb_in_use = env->tlb->nb_tlb;
      env->CP0_Wired = 0;
      env->CP0_GlobalNumber = (cs->cpu_index & 0xFF) << CP0GN_VPId;
-    env->CP0_EBase = (cs->cpu_index & 0x3FF);
-    if (mips_um_ksegs_enabled()) {
-        env->CP0_EBase |= 0x40000000;
-    } else {
-        env->CP0_EBase |= (int32_t)0x80000000;
-    }
+    env->CP0_EBase = (cs->cpu_index & 0x3FF) | (int32_t)0x80000000;
      if (env->CP0_Config3 & (1 << CP0C3_CMGCR)) {
          env->CP0_CMGCRBase = 0x1fbf8000 >> 4;
      }
diff --git a/target/mips/cpu.h b/target/mips/cpu.h
index 0a085643a3f1..3411cbc37825 100644
--- a/target/mips/cpu.h
+++ b/target/mips/cpu.h
@@ -1299,8 +1299,6 @@ uint64_t cpu_mips_phys_to_kseg0(void *opaque, uint64_t 
addr);
  uint64_t cpu_mips_kvm_um_phys_to_kseg0(void *opaque, uint64_t addr);
  uint64_t cpu_mips_kseg1_to_phys(void *opaque, uint64_t addr);
  uint64_t cpu_mips_phys_to_kseg1(void *opaque, uint64_t addr);
-bool mips_um_ksegs_enabled(void);
-void mips_um_ksegs_enable(void);
#if !defined(CONFIG_USER_ONLY) diff --git a/target/mips/kvm.c b/target/mips/kvm.c
index bcb8e06b2cb4..c14e8f550fcc 100644
--- a/target/mips/kvm.c
+++ b/target/mips/kvm.c
@@ -1268,25 +1268,16 @@ int kvm_arch_msi_data_to_gsi(uint32_t data)
int mips_kvm_type(MachineState *machine, const char *vm_type)
  {
-#if defined(KVM_CAP_MIPS_VZ) || defined(KVM_CAP_MIPS_TE)
+#if defined(KVM_CAP_MIPS_VZ)
      int r;
      KVMState *s = KVM_STATE(machine->accelerator);
-#endif
-#if defined(KVM_CAP_MIPS_VZ)
      r = kvm_check_extension(s, KVM_CAP_MIPS_VZ);
      if (r > 0) {
          return KVM_VM_MIPS_VZ;
      }
  #endif
-#if defined(KVM_CAP_MIPS_TE)
-    r = kvm_check_extension(s, KVM_CAP_MIPS_TE);
-    if (r > 0) {
-        return KVM_VM_MIPS_TE;
-    }
-#endif
-
      return -1;
  }
diff --git a/target/mips/sysemu/addr.c b/target/mips/sysemu/addr.c
index 86f1c129c9f4..4f025be44a1d 100644
--- a/target/mips/sysemu/addr.c
+++ b/target/mips/sysemu/addr.c
@@ -23,8 +23,6 @@
  #include "qemu/osdep.h"
  #include "cpu.h"
-static int mips_um_ksegs;
-
  uint64_t cpu_mips_kseg0_to_phys(void *opaque, uint64_t addr)
  {
      return addr & 0x1fffffffll;
@@ -35,11 +33,6 @@ uint64_t cpu_mips_phys_to_kseg0(void *opaque, uint64_t addr)
      return addr | ~0x7fffffffll;
  }
-uint64_t cpu_mips_kvm_um_phys_to_kseg0(void *opaque, uint64_t addr)
-{
-    return addr | 0x40000000ll;
-}
-
  uint64_t cpu_mips_kseg1_to_phys(void *opaque, uint64_t addr)
  {
      return addr & 0x1fffffffll;
@@ -49,13 +42,3 @@ uint64_t cpu_mips_phys_to_kseg1(void *opaque, uint64_t addr)
  {
      return (addr & 0x1fffffffll) | 0xffffffffa0000000ll;
  }
-
-bool mips_um_ksegs_enabled(void)
-{
-    return mips_um_ksegs;
-}
-
-void mips_um_ksegs_enable(void)
-{
-    mips_um_ksegs = 1;
-}
diff --git a/target/mips/sysemu/physaddr.c b/target/mips/sysemu/physaddr.c
index 1918633aa1c4..2970df8a0981 100644
--- a/target/mips/sysemu/physaddr.c
+++ b/target/mips/sysemu/physaddr.c
@@ -130,19 +130,6 @@ int get_physical_address(CPUMIPSState *env, hwaddr 
*physical,
      /* effective address (modified for KVM T&E kernel segments) */
      target_ulong address = real_address;
- if (mips_um_ksegs_enabled()) {
-        /* KVM T&E adds guest kernel segments in useg */
-        if (real_address >= KVM_KSEG0_BASE) {
-            if (real_address < KVM_KSEG2_BASE) {

We can now remove these 2 definitions (I can squash when applying).

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

-                /* kseg0 */
-                address += KSEG0_BASE - KVM_KSEG0_BASE;
-            } else if (real_address <= USEG_LIMIT) {
-                /* kseg2/3 */
-                address += KSEG2_BASE - KVM_KSEG2_BASE;
-            }
-        }
-    }
-
      if (address <= USEG_LIMIT) {
          /* useg */
          uint16_t segctl;




reply via email to

[Prev in Thread] Current Thread [Next in Thread]