Re: [SeaBIOS] [PATCH 1/3] Add generic qemu detection

[Gleb Natapov]

On Tue, Sep 03, 2013 at 02:37:41PM +0200, Gerd Hoffmann wrote:
> This patch adds support for detecting whenever SeaBIOS runs on qemu
> or not.  This is done by looking at the northbridge (pci device 00:00.0)
> and check the subsystem id.  Most pci devices emulated by qemu -- the
> two northbridges i440fx and q35 included -- have a subsystem id of
> "1af4:1100".
>
> In case the subsystem ID matches set PF_QEMU, log a message (including
> the northbridge found while being at it) and also check for kvm.

Why condition KVM check on QEMU?
> Signed-off-by: Gerd Hoffmann
>
> src/paravirt.c | 42 ++++++++++++++++++++++++++++++++++++------
>  src/paravirt.h |  1 +
>  2 files changed, 37 insertions(+), 6 deletions(-)
>
> diff --git a/src/paravirt.c b/src/paravirt.c
> index d1a5d3e..ea9fa9a 100644
> --- a/src/paravirt.c
> +++ b/src/paravirt.c
> @@ -19,6 +19,7 @@
>  #include "acpi.h" // acpi_setup
>  #include "mptable.h" // mptable_setup
>  #include "pci.h" // create_pirtable
> +#include "pci_regs.h" // create_pirtable
>  #include "xen.h" // xen_biostable_setup
>
> // Amount of continuous ram under 4Gig
> @@ -33,10 +34,8 @@ int PlatformRunningOn VARFSEG;
>   */
>  #define KVM_CPUID_SIGNATURE     0x40000000
>
> -static void kvm_preinit(void)
> +static void kvm_detect(void)
>  {
> if (!CONFIG_QEMU)
>    return;
> unsigned int eax, ebx, ecx, edx;
>    char signature[13];
>
> @@ -52,9 +51,43 @@ static void kvm_preinit(void)
>      }
>  }
>
> +void qemu_detect(void)
> +{
> if (!CONFIG_QEMU_HARDWARE)
>    return;
> // check northbridge @ 00:00.0
> u16 v = pci_config_readw(0, PCI_VENDOR_ID);
> if (v == 0x0000 || v == 0xffff)
>    return;
> u16 d = pci_config_readw(0, PCI_DEVICE_ID);
> u16 sv = pci_config_readw(0, PCI_SUBSYSTEM_VENDOR_ID);
> u16 sd = pci_config_readw(0, PCI_SUBSYSTEM_ID);
> if (sv != 0x1af4 || /* Red Hat, Inc */
>    sd != 0x1100)   /* Qemu virtual machine */
>    return;
> PlatformRunningOn |= PF_QEMU;
> switch (d) {
> case 0x1237:
>    dprintf(1, "Running on QEMU (i440fx)\n");
>    break;
> case 0x29c0:
>    dprintf(1, "Running on QEMU (q35)\n");
>    break;
> default:
>    dprintf(1, "Running on QEMU (unknown nb: %04x:%04x)\n", v, d);
>    break;
> }
> kvm_detect();
>
> +}
>
> void
>  qemu_preinit(void)
>  {
> qemu_detect();
> if (!CONFIG_QEMU)
>        return;
>
> @@ -63,9 +96,6 @@ qemu_preinit(void)
>          return;
>      }
> PlatformRunningOn = PF_QEMU;
> kvm_preinit();
> // On emulators, get memory size from nvram.
>    u32 rs = ((inb_cmos(CMOS_MEM_EXTMEM2_LOW) << 16)
>              | (inb_cmos(CMOS_MEM_EXTMEM2_HIGH) << 24));
>
> diff --git a/src/paravirt.h b/src/paravirt.h
> index fce5af9..7fc00b0 100644
> --- a/src/paravirt.h
> +++ b/src/paravirt.h
> @@ -24,6 +24,7 @@ static inline int runningOnKVM(void) {
>      return CONFIG_QEMU && GET_GLOBAL(PlatformRunningOn) & PF_KVM;
>  }
>
> +void qemu_detect(void);
>  void qemu_preinit(void);
>  void qemu_platform_setup(void);
>  void qemu_cfg_init(void);
> -- 
> 1.8.3.1
>
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