[PATCH v2 2/2] accel/mshv: enable amx tiles support for guests

["Doru Blânzeanu" <dblanzeanu@linux.microsoft.com>]

The AMX tiles feature uses a larger than 4kB area in xsave.
This fix removes the code that disables AMX tiles in the partition and it
adjusts the supported CPUID to advertise AMX tiles.

Signed-off-by: Doru Blânzeanu <dblanzeanu@linux.microsoft.com>
---
 accel/mshv/mshv-all.c       | 18 +++++-------------
 target/i386/mshv/mshv-cpu.c | 16 ----------------
 2 files changed, 5 insertions(+), 29 deletions(-)

diff --git a/accel/mshv/mshv-all.c b/accel/mshv/mshv-all.c
index 725ccd0511..99b2b3362a 100644
--- a/accel/mshv/mshv-all.c
+++ b/accel/mshv/mshv-all.c
@@ -187,7 +187,6 @@ static int create_partition(int mshv_fd, int *vm_fd)
 {
     int ret;
     uint64_t pt_flags, host_proc_features;
-    union hv_partition_processor_xsave_features disabled_xsave_features;
     union hv_partition_processor_features disabled_partition_features = {0};
 
     struct mshv_create_partition_v2 args = {0};
@@ -200,17 +199,6 @@ static int create_partition(int mshv_fd, int *vm_fd)
                (1ULL << MSHV_PT_BIT_GPA_SUPER_PAGES) |
                (1ULL << MSHV_PT_BIT_CPU_AND_XSAVE_FEATURES);
 
-    /* enable all */
-    disabled_xsave_features.as_uint64 = 0;
-    /*
-     * AMX TILE XSAVE state (XTILE_DATA) is 8KB, which exceeds the
-     * current fixed 4KB XSAVE buffer size.
-     */
-    disabled_xsave_features.amx_tile_support = 1;
-    disabled_xsave_features.amx_bf16_support = 1;
-    disabled_xsave_features.amx_int8_support = 1;
-    disabled_xsave_features.amx_fp16_support = 1;
-
     /*
      * query host for supported processor features and disable unsupported
      * features: (0 means supported, 1 means disabled, hence the negation)
@@ -238,10 +226,14 @@ static int create_partition(int mshv_fd, int *vm_fd)
     args.pt_cpu_fbanks[0] |= disabled_partition_features.as_uint64[0];
     args.pt_cpu_fbanks[1] |= disabled_partition_features.as_uint64[1];
 
+    /*
+     * for now, all the xsave features are enabled, the filtering is only done
+     * at the CPUID level
+     * TODO: filter the xsave features based on the CPUID derived from Cpu model
+     */
     /* populate args structure */
     args.pt_flags = pt_flags;
     args.pt_isolation = MSHV_PT_ISOLATION_NONE;
-    args.pt_disabled_xsave = disabled_xsave_features.as_uint64;
     args.pt_num_cpu_fbanks = MSHV_NUM_CPU_FEATURES_BANKS;
 
     ret = ioctl(mshv_fd, MSHV_CREATE_PARTITION, &args);
diff --git a/target/i386/mshv/mshv-cpu.c b/target/i386/mshv/mshv-cpu.c
index 5b845b3e4e..21a3534578 100644
--- a/target/i386/mshv/mshv-cpu.c
+++ b/target/i386/mshv/mshv-cpu.c
@@ -2234,22 +2234,6 @@ uint32_t mshv_get_supported_cpuid(uint32_t func, uint32_t idx, int reg)
          */
         ret &= ~CPUID_7_0_ECX_LA57;
     }
-    if (func == 0x07 && idx == 0 && reg == R_EDX) {
-        /*
-         * AMX TILE XSAVE state (XTILE_DATA) is 8KB, which exceeds the
-         * current fixed 4KB XSAVE buffer size. Filter until buffer
-         * sizing is computed dynamically from CPUID.
-         */
-        ret &= ~CPUID_7_0_EDX_AMX_TILE;
-        ret &= ~CPUID_7_0_EDX_AMX_BF16;
-        ret &= ~CPUID_7_0_EDX_AMX_INT8;
-    }
-    if (func == 0x07 && idx == 1 && reg == R_EAX) {
-        ret &= ~CPUID_7_1_EAX_AMX_FP16;
-    }
-    if (func == 0x07 && idx == 1 && reg == R_EDX) {
-        ret &= ~CPUID_7_1_EDX_AMX_COMPLEX;
-    }
 
     return ret;
 }
-- 
2.53.0