[PATCH v9 0/1] MR4409: wineboot: Compute and write the TSC frequency to registry ~Mhz.

[Marc-Aurel Zent (＠marzent)]

This is an attempt to upstream a set of Proton patches that correct the value of HKEY_LOCAL_MACHINE\\HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\*\\~MHz to not be the maximum frequency of the processor, but the calibrated TSC.

Some games like Horizon Zero Dawn and most likely some more obscure benchmark/profiling tools use this as indicated in this forum post: https://community.osr.com/discussion/288014/how-to-find-out-tsc-frequency

The last comment also suggests querying the above registry key for the TSC.

To my understanding the calibration code has been successfully in use for some time now without any known issues.

I tried to be as faithful to the original history as possible with separating out my changes into their own commits.

If everything should be squashed to be prettier, just let me know!

FYI @rbernon

--
  v9: wineboot: Compute and write the TSC frequency to registry ~Mhz.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/4409

[PATCH v9 1/1] wineboot: Compute and write the TSC frequency to registry ~Mhz.

[Rémi Bernon]

From: Rémi Bernon <rbernon(a)codeweavers.com>

In HKEY_LOCAL_MACHINE\\HARDWARE\\DESCRIPTION\\System\\CentralProcessor

Some games such as Horizon Zero Dawn use this registry value to
correlate values from rtdsc to real time.

Returning the nominal/maximum cpu frequency here causes the game to run
in slow motion as it may not match the tsc frequency of the processor.

Based on patches from Arkadiusz Hiler and Joshua Ashton.
---
 programs/wineboot/wineboot.c | 114 ++++++++++++++++++++++++++++++++++-
 1 file changed, 113 insertions(+), 1 deletion(-)

diff --git a/programs/wineboot/wineboot.c b/programs/wineboot/wineboot.c
index 728c41fffa9..ba09addfc37 100644
--- a/programs/wineboot/wineboot.c
+++ b/programs/wineboot/wineboot.c
@@ -240,12 +240,120 @@ static void initialize_xstate_features(struct _KUSER_SHARED_DATA *data)
     TRACE("XSAVE feature 2 %#x, %#x, %#x, %#x.\n", regs[0], regs[1], regs[2], regs[3]);
 }
 
+static BOOL is_tsc_trusted_by_the_kernel(void)
+{
+    char buf[4] = {0};
+    DWORD num_read;
+    HANDLE handle;
+    BOOL ret = TRUE;
+
+    /* Darwin for x86-64 uses the TSC internally for timekeeping, so it can always
+     * be trusted.
+     * For BSDs there seems to be no unified interface to query TSC quality.
+     * If there is a sysfs entry with clocksource information, use it to check though. */
+    handle = CreateFileW( L"\\??\\unix\\sys\\bus\\clocksource\\devices\\clocksource0\\current_clocksource",
+                          GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, 0 );
+    if (handle == INVALID_HANDLE_VALUE) return TRUE;
+
+    if (ReadFile( handle, buf, sizeof(buf) - 1, &num_read, NULL ) && strcmp( "tsc", buf ))
+        ret = FALSE;
+
+    CloseHandle( handle );
+    return ret;
+}
+
+static UINT64 read_tsc_frequency(void)
+{
+    UINT64 freq = 0;
+    LONGLONG time0, time1, tsc0, tsc1, tsc2, tsc3, freq0, freq1, error;
+    BOOL has_rdtscp = FALSE;
+    unsigned int aux;
+    UINT retries = 50;
+    int regs[4];
+
+    if (!is_tsc_trusted_by_the_kernel())
+    {
+        WARN( "Failed to compute TSC frequency, not trusted by the kernel.\n" );
+        return 0;
+    }
+
+    __cpuid(regs, 1);
+    if (!(regs[3] & (1 << 4)))
+    {
+        WARN( "Failed to compute TSC frequency, RDTSC instruction not supported.\n" );
+        return 0;
+    }
+
+    __cpuid( regs, 0x80000000 );
+    if (regs[0] < 0x80000007)
+    {
+        WARN( "Failed to compute TSC frequency, unable to check invariant TSC.\n" );
+        return 0;
+    }
+
+    /* check for invariant tsc bit */
+    __cpuid( regs, 0x80000007 );
+    if (!(regs[3] & (1 << 8)))
+    {
+        WARN( "Failed to compute TSC frequency, no invariant TSC.\n" );
+        return 0;
+    }
+
+    /* check for rdtscp support bit */
+    __cpuid( regs, 0x80000001 );
+    if ((regs[3] & (1 << 27))) has_rdtscp = TRUE;
+
+    /* FIXME: implement a better frequency measurement here. */
+    do
+    {
+        if (has_rdtscp)
+        {
+            tsc0 = __rdtscp( &aux );
+            time0 = RtlGetSystemTimePrecise();
+            tsc1 = __rdtscp( &aux );
+            Sleep( 1 );
+            tsc2 = __rdtscp( &aux );
+            time1 = RtlGetSystemTimePrecise();
+            tsc3 = __rdtscp( &aux );
+        }
+        else
+        {
+            tsc0 = __rdtsc(); __cpuid( regs, 0 );
+            time0 = RtlGetSystemTimePrecise();
+            tsc1 = __rdtsc(); __cpuid( regs, 0 );
+            Sleep(1);
+            tsc2 = __rdtsc(); __cpuid( regs, 0 );
+            time1 = RtlGetSystemTimePrecise();
+            tsc3 = __rdtsc(); __cpuid( regs, 0 );
+        }
+
+        freq0 = (tsc2 - tsc0) * 10000000 / (time1 - time0);
+        freq1 = (tsc3 - tsc1) * 10000000 / (time1 - time0);
+        error = llabs( (freq1 - freq0) * 1000000 / min( freq1, freq0 ) );
+    }
+    while (error > 500 && --retries);
+
+    if (!retries) WARN( "TSC frequency calibration failed, unstable TSC?\n" );
+    else
+    {
+        freq = (freq0 + freq1) / 2;
+        TRACE( "TSC frequency calibration complete, found %I64u Hz\n", freq );
+    }
+
+    return freq;
+}
+
 #else
 
 static void initialize_xstate_features(struct _KUSER_SHARED_DATA *data)
 {
 }
 
+static UINT64 read_tsc_frequency(void)
+{
+    return 0;
+}
+
 #endif
 
 static void create_user_shared_data(void)
@@ -666,6 +774,7 @@ static void create_hardware_registry_keys(void)
     SYSTEM_CPU_INFORMATION sci;
     PROCESSOR_POWER_INFORMATION* power_info;
     ULONG sizeof_power_info = sizeof(PROCESSOR_POWER_INFORMATION) * NtCurrentTeb()->Peb->NumberOfProcessors;
+    UINT64 tsc_frequency = read_tsc_frequency();
     ULONG name_buffer[16];
     WCHAR id[60], vendorid[13];
 
@@ -736,13 +845,16 @@ static void create_hardware_registry_keys(void)
         if (!RegCreateKeyExW( cpu_key, numW, 0, NULL, REG_OPTION_VOLATILE,
                               KEY_ALL_ACCESS, NULL, &hkey, NULL ))
         {
+            DWORD tsc_freq_mhz = (DWORD)(tsc_frequency / 1000000ull); /* Hz -> Mhz */
+            if (!tsc_freq_mhz) tsc_freq_mhz = power_info[i].MaxMhz;
+
             RegSetValueExW( hkey, L"FeatureSet", 0, REG_DWORD, (BYTE *)&sci.ProcessorFeatureBits, sizeof(DWORD) );
             set_reg_value( hkey, L"Identifier", id );
             /* TODO: report ARM properly */
             RegSetValueExA( hkey, "ProcessorNameString", 0, REG_SZ, (const BYTE *)name_buffer,
                             strlen( (char *)name_buffer ) + 1 );
             set_reg_value( hkey, L"VendorIdentifier", vendorid );
-            RegSetValueExW( hkey, L"~MHz", 0, REG_DWORD, (BYTE *)&power_info[i].MaxMhz, sizeof(DWORD) );
+            RegSetValueExW( hkey, L"~MHz", 0, REG_DWORD, (BYTE *)&tsc_freq_mhz, sizeof(DWORD) );
             RegCloseKey( hkey );
         }
         if (sci.ProcessorArchitecture != PROCESSOR_ARCHITECTURE_ARM &&
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/4409

[Rémi Bernon]

Rémi Bernon (@rbernon) commented about programs/wineboot/wineboot.c:
> +        freq = (freq0 + freq1) / 2;
> +        TRACE( "TSC frequency calibration complete, found %I64u Hz\n", freq );
> +    }
> +
> +    return freq;
> +}
> +
>  #else
>
> static void initialize_xstate_features(struct _KUSER_SHARED_DATA *data)
>  {
>  }
>
> +static UINT64 read_tsc_frequency(void)
> +{
> +    return 0;
> I actually meant something like `FIXME("TSC frequency calibration not implemented\n");` here, but it doesn't matter very much.

LGTM otherwise, thanks!

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/4409#note_52574

[PATCH v9 0/1] MR4409: wineboot: Compute and write the TSC frequency to registry ~Mhz. - approved

[Rémi Bernon]

This merge request was approved by Rémi Bernon.
-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/4409