diff mbox series

[v4,05/17] i386/pc_sysfw: Ensure sysfw flash configuration does not conflict with IGVM

Message ID c58c4b5cc8a35245b7ef31fefcc67a72e6346a07.1720004383.git.roy.hopkins@suse.com
State New
Headers show
Series Introduce support for IGVM files | expand

Commit Message

Roy Hopkins July 3, 2024, 11:05 a.m. UTC
When using an IGVM file the configuration of the system firmware is
defined by IGVM directives contained in the file. In this case the user
should not configure any pflash devices.

This commit skips initialization of the ROM mode when pflash0 is not set
then checks to ensure no pflash devices have been configured when using
IGVM, exiting with an error message if this is not the case.

Signed-off-by: Roy Hopkins <roy.hopkins@suse.com>
---
 hw/i386/pc_sysfw.c | 31 ++++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

Comments

Daniel P. Berrangé July 24, 2024, 5:13 p.m. UTC | #1
On Wed, Jul 03, 2024 at 12:05:43PM +0100, Roy Hopkins wrote:
> When using an IGVM file the configuration of the system firmware is
> defined by IGVM directives contained in the file. In this case the user
> should not configure any pflash devices.
> 
> This commit skips initialization of the ROM mode when pflash0 is not set
> then checks to ensure no pflash devices have been configured when using
> IGVM, exiting with an error message if this is not the case.
> 
> Signed-off-by: Roy Hopkins <roy.hopkins@suse.com>
> ---
>  hw/i386/pc_sysfw.c | 31 ++++++++++++++++++++++++++++---
>  1 file changed, 28 insertions(+), 3 deletions(-)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

> 
> diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> index ef80281d28..f5e40b3ef6 100644
> --- a/hw/i386/pc_sysfw.c
> +++ b/hw/i386/pc_sysfw.c
> @@ -219,7 +219,13 @@ void pc_system_firmware_init(PCMachineState *pcms,
>      BlockBackend *pflash_blk[ARRAY_SIZE(pcms->flash)];
>  
>      if (!pcmc->pci_enabled) {
> -        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
> +        /*
> +         * If an IGVM file is specified then the firmware must be provided
> +         * in the IGVM file.
> +         */
> +        if (!X86_MACHINE(pcms)->igvm) {
> +            x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
> +        }

IIUC from looking at x86_bios_rom_init, the 'firmware' machine property
will be NULL if no -bios arg is given, and non-NULL if -bios is set,
so we can give an error message is -bios is set, while doing the right
thing if unset.

IOW I think this could look more like

        X86MachineState *x86ms = X86_MACHINE(pcms);
	if (x86ms->igvm) {
	    if (x86ms->firmware) {
                error_report("Firmware ROM cannot be configured when "
                             "using IGVM");
                exit(1);
	    }
	} else {
            x86_bios_rom_init(x86ms, "bios.bin", rom_memory, true);
        }

>          return;
>      }
>  
> @@ -239,8 +245,13 @@ void pc_system_firmware_init(PCMachineState *pcms,
>      }
>  
>      if (!pflash_blk[0]) {
> -        /* Machine property pflash0 not set, use ROM mode */
> -        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, false);
> +        /*
> +         * Machine property pflash0 not set, use ROM mode unless using IGVM,
> +         * in which case the firmware must be provided by the IGVM file.
> +         */
> +        if (!X86_MACHINE(pcms)->igvm) {
> +            x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, false);
> +        }

Same as earlier

>      } else {
>          if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
>              /*
> @@ -256,6 +267,20 @@ void pc_system_firmware_init(PCMachineState *pcms,
>      }
>  
>      pc_system_flash_cleanup_unused(pcms);
> +
> +    /*
> +     * The user should not have specified any pflash devices when using IGVM
> +     * to configure the guest.
> +     */
> +    if (X86_MACHINE(pcms)->igvm) {
> +        for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
> +            if (pcms->flash[i]) {
> +                error_report("pflash devices cannot be configured when "
> +                             "using IGVM");
> +                exit(1);
> +            }
> +        }
> +    }
>  }
>  
>  void x86_firmware_configure(hwaddr gpa, void *ptr, int size)
> -- 
> 2.43.0
> 

With regards,
Daniel
Roy Hopkins Aug. 13, 2024, 10:42 a.m. UTC | #2
On Wed, 2024-07-24 at 18:13 +0100, Daniel P. Berrangé wrote:
> On Wed, Jul 03, 2024 at 12:05:43PM +0100, Roy Hopkins wrote:
> > When using an IGVM file the configuration of the system firmware is
> > defined by IGVM directives contained in the file. In this case the user
> > should not configure any pflash devices.
> > 
> > This commit skips initialization of the ROM mode when pflash0 is not set
> > then checks to ensure no pflash devices have been configured when using
> > IGVM, exiting with an error message if this is not the case.
> > 
> > Signed-off-by: Roy Hopkins <roy.hopkins@suse.com>
> > ---
> >  hw/i386/pc_sysfw.c | 31 ++++++++++++++++++++++++++++---
> >  1 file changed, 28 insertions(+), 3 deletions(-)
> 
> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
> 
> > 
> > diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> > index ef80281d28..f5e40b3ef6 100644
> > --- a/hw/i386/pc_sysfw.c
> > +++ b/hw/i386/pc_sysfw.c
> > @@ -219,7 +219,13 @@ void pc_system_firmware_init(PCMachineState *pcms,
> >      BlockBackend *pflash_blk[ARRAY_SIZE(pcms->flash)];
> >  
> >      if (!pcmc->pci_enabled) {
> > -        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
> > +        /*
> > +         * If an IGVM file is specified then the firmware must be provided
> > +         * in the IGVM file.
> > +         */
> > +        if (!X86_MACHINE(pcms)->igvm) {
> > +            x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory,
> > true);
> > +        }
> 
> IIUC from looking at x86_bios_rom_init, the 'firmware' machine property
> will be NULL if no -bios arg is given, and non-NULL if -bios is set,
> so we can give an error message is -bios is set, while doing the right
> thing if unset.
> 
> [Snip]

I looked at changing this, but the `firmware` machine property is not NULL even
if no -bios arg is provided. This is because `default_machine_opts" in pc_q35.c
and pc_piixx.c both provide a default file for the firmware if not provided.
Therefore I've left this unchanged.

> 
> >          return;
> >      }
> >  
> > @@ -239,8 +245,13 @@ void pc_system_firmware_init(PCMachineState *pcms,
> >      }
> >  
> >      if (!pflash_blk[0]) {
> > -        /* Machine property pflash0 not set, use ROM mode */
> > -        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory,
> > false);
> > +        /*
> > +         * Machine property pflash0 not set, use ROM mode unless using
> > IGVM,
> > +         * in which case the firmware must be provided by the IGVM file.
> > +         */
> > +        if (!X86_MACHINE(pcms)->igvm) {
> > +            x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory,
> > false);
> > +        }
> 
> Same as earlier
> 
> >      } else {
> >          if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
> >              /*
> > @@ -256,6 +267,20 @@ void pc_system_firmware_init(PCMachineState *pcms,
> >      }
> >  
> >      pc_system_flash_cleanup_unused(pcms);
> > +
> > +    /*
> > +     * The user should not have specified any pflash devices when using
> > IGVM
> > +     * to configure the guest.
> > +     */
> > +    if (X86_MACHINE(pcms)->igvm) {
> > +        for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
> > +            if (pcms->flash[i]) {
> > +                error_report("pflash devices cannot be configured when "
> > +                             "using IGVM");
> > +                exit(1);
> > +            }
> > +        }
> > +    }
> >  }
> >  
> >  void x86_firmware_configure(hwaddr gpa, void *ptr, int size)
> > -- 
> > 2.43.0
> > 
> 
> With regards,
> Daniel
diff mbox series

Patch

diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
index ef80281d28..f5e40b3ef6 100644
--- a/hw/i386/pc_sysfw.c
+++ b/hw/i386/pc_sysfw.c
@@ -219,7 +219,13 @@  void pc_system_firmware_init(PCMachineState *pcms,
     BlockBackend *pflash_blk[ARRAY_SIZE(pcms->flash)];
 
     if (!pcmc->pci_enabled) {
-        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
+        /*
+         * If an IGVM file is specified then the firmware must be provided
+         * in the IGVM file.
+         */
+        if (!X86_MACHINE(pcms)->igvm) {
+            x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
+        }
         return;
     }
 
@@ -239,8 +245,13 @@  void pc_system_firmware_init(PCMachineState *pcms,
     }
 
     if (!pflash_blk[0]) {
-        /* Machine property pflash0 not set, use ROM mode */
-        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, false);
+        /*
+         * Machine property pflash0 not set, use ROM mode unless using IGVM,
+         * in which case the firmware must be provided by the IGVM file.
+         */
+        if (!X86_MACHINE(pcms)->igvm) {
+            x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, false);
+        }
     } else {
         if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
             /*
@@ -256,6 +267,20 @@  void pc_system_firmware_init(PCMachineState *pcms,
     }
 
     pc_system_flash_cleanup_unused(pcms);
+
+    /*
+     * The user should not have specified any pflash devices when using IGVM
+     * to configure the guest.
+     */
+    if (X86_MACHINE(pcms)->igvm) {
+        for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
+            if (pcms->flash[i]) {
+                error_report("pflash devices cannot be configured when "
+                             "using IGVM");
+                exit(1);
+            }
+        }
+    }
 }
 
 void x86_firmware_configure(hwaddr gpa, void *ptr, int size)