On Thu, May 30, 2024 at 1:17 PM Pankaj Gupta <pankaj.gupta@xxxxxxx> wrote:
> if (bios_size <= 0 ||
> (bios_size % 65536) != 0) {
> - goto bios_error;
> + if (!machine_require_guest_memfd(MACHINE(x86ms))) {
> + g_warning("%s: Unaligned BIOS size %d", __func__, bios_size);
> + goto bios_error;
> + }
Why is this not needed for SEV-SNP? (The bios_size <= 0 case
definitely should be an error).
I'll just drop this change.
> + }
> + if (machine_require_guest_memfd(MACHINE(x86ms))) {
> + memory_region_init_ram_guest_memfd(&x86ms->bios, NULL, "pc.bios",
> + bios_size, &error_fatal);
> + } else {
> + memory_region_init_ram(&x86ms->bios, NULL, "pc.bios",
> + bios_size, &error_fatal);
> }
> - memory_region_init_ram(&x86ms->bios, NULL, "pc.bios", bios_size,
> - &error_fatal);
> if (sev_enabled()) {
> /*
> * The concept of a "reset" simply doesn't exist for
> @@ -1023,9 +1031,11 @@ void x86_bios_rom_init(X86MachineState *x86ms, const char *default_firmware,
> }
> g_free(filename);
>
> - /* map the last 128KB of the BIOS in ISA space */
> - x86_isa_bios_init(&x86ms->isa_bios, rom_memory, &x86ms->bios,
> - !isapc_ram_fw);
> + if (!machine_require_guest_memfd(MACHINE(x86ms))) {
> + /* map the last 128KB of the BIOS in ISA space */
> + x86_isa_bios_init(&x86ms->isa_bios, rom_memory, &x86ms->bios,
> + !isapc_ram_fw);
> + }
>
> /* map all the bios at the top of memory */
> memory_region_add_subregion(rom_memory,
> --
> 2.34.1
>
On Thu, May 30, 2024 at 1:17 PM Pankaj Gupta <pankaj.gupta@xxxxxxx> wrote:
>
> From: Michael Roth <michael.roth@xxxxxxx>
>
> When guest_memfd is enabled, the BIOS is generally part of the initial
> encrypted guest image and will be accessed as private guest memory. Add
> the necessary changes to set up the associated RAM region with a
> guest_memfd backend to allow for this.
>
> Current support centers around using -bios to load the BIOS data.
> Support for loading the BIOS via pflash requires additional enablement
> since those interfaces rely on the use of ROM memory regions which make
> use of the KVM_MEM_READONLY memslot flag, which is not supported for
> guest_memfd-backed memslots.
>
> Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
> Signed-off-by: Pankaj Gupta <pankaj.gupta@xxxxxxx>
> ---
> hw/i386/x86-common.c | 22 ++++++++++++++++------
> 1 file changed, 16 insertions(+), 6 deletions(-)
>
> diff --git a/hw/i386/x86-common.c b/hw/i386/x86-common.c
> index f41cb0a6a8..059de65f36 100644
> --- a/hw/i386/x86-common.c
> +++ b/hw/i386/x86-common.c
> @@ -999,10 +999,18 @@ void x86_bios_rom_init(X86MachineState *x86ms, const char *default_firmware,
> }
> if (bios_size <= 0 ||
> (bios_size % 65536) != 0) {
> - goto bios_error;
> + if (!machine_require_guest_memfd(MACHINE(x86ms))) {
> + g_warning("%s: Unaligned BIOS size %d", __func__, bios_size);
> + goto bios_error;
> + }
> + }
> + if (machine_require_guest_memfd(MACHINE(x86ms))) {
> + memory_region_init_ram_guest_memfd(&x86ms->bios, NULL, "pc.bios",
> + bios_size, &error_fatal);
> + } else {
> + memory_region_init_ram(&x86ms->bios, NULL, "pc.bios",
> + bios_size, &error_fatal);
> }
> - memory_region_init_ram(&x86ms->bios, NULL, "pc.bios", bios_size,
> - &error_fatal);
> if (sev_enabled()) {
> /*
> * The concept of a "reset" simply doesn't exist for
> @@ -1023,9 +1031,11 @@ void x86_bios_rom_init(X86MachineState *x86ms, const char *default_firmware,
> }
> g_free(filename);
>
> - /* map the last 128KB of the BIOS in ISA space */
> - x86_isa_bios_init(&x86ms->isa_bios, rom_memory, &x86ms->bios,
> - !isapc_ram_fw);
> + if (!machine_require_guest_memfd(MACHINE(x86ms))) {
> + /* map the last 128KB of the BIOS in ISA space */
> + x86_isa_bios_init(&x86ms->isa_bios, rom_memory, &x86ms->bios,
> + !isapc_ram_fw);
> + }
>
> /* map all the bios at the top of memory */
> memory_region_add_subregion(rom_memory,
> --
> 2.34.1
>
