On Thursday 16 July 2009 08:12:15 Jordan Justen wrote:
> Previously the KVM kernel module would allocate the address range
> of 0xfffbc000-0xfffbcfff for the EPT Indentity Page Tables.
> A separate patch is moving that to 0xfeffc000-0xfeffcfff.
Hi Jordan
You need one more patch for upstream kvm, to include the modification of
vmx.h.
>
> This patch updates qemu-kvm to move the VMX TSS Pages & update the
> KVM BIOS code to update the E820 BIOS call memory reservations.
>
> Previously, the VMC TSS Pages were located at 0xfffbd000-0xfffbffff.
> This change moved them to 0xfeffd000-0xfeffffff.
>
> This change also updates the KVM bios such that the E820 locations
> are returned properly for these two changes.
>
> From a high level, these are the effects of these two changes:
>
> Previously, the KVM would only accommodate a 256KB BIOS image. With
> these changes, the BIOS image may now grow to 16MB.
>
> Motivation for making these changes:
>
> A larger firmware image size allows alternative BIOS images to be
> used with KVM. Some possible uses are to enable UEFI firmware
> or coreboot firmware. Additionally, an alternative firmware might
> include a linux kernel+initrd payload, which would require several
> megabytes.
I think if you update bios to UEFI, the E820 should be represented by UEFI
rather than current bios?
--
regards
Yang, Sheng
> Signed-off-by: Jordan Justen <jordan.l.justen@xxxxxxxxx>
> ---
> kvm/bios/rombios.c | 8 ++++----
> kvm/include/x86/asm/vmx.h | 2 +-
> qemu-kvm-x86.c | 2 +-
> 3 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/kvm/bios/rombios.c b/kvm/bios/rombios.c
> index 6186199..2d0c153 100644
> --- a/kvm/bios/rombios.c
> +++ b/kvm/bios/rombios.c
> @@ -4596,14 +4596,14 @@ ASM_END
> case 5:
> /* 4 pages before the bios, 3 pages for vmx tss
> pages, * the other page for EPT real mode pagetable */
> - set_e820_range(ES, regs.u.r16.di, 0xfffbc000L,
> - 0xfffc0000L, 0, 0, 2);
> + set_e820_range(ES, regs.u.r16.di, 0xfeffc000L,
> + 0xff000000L, 0, 0, 2);
> regs.u.r32.ebx = 6;
> break;
> case 6:
> - /* 256KB BIOS area at the end of 4 GB */
> + /* 16MB BIOS area at the end of 4 GB */
> set_e820_range(ES, regs.u.r16.di,
> - 0xfffc0000L, 0x00000000L ,0, 0, 2);
> + 0xff000000L, 0x00000000L ,0, 0, 2);
> if (extra_highbits_memory_size ||
> extra_lowbits_memory_size) regs.u.r32.ebx = 7;
> else
> diff --git a/kvm/include/x86/asm/vmx.h b/kvm/include/x86/asm/vmx.h
> index df8d4f9..99e2bb9 100644
> --- a/kvm/include/x86/asm/vmx.h
> +++ b/kvm/include/x86/asm/vmx.h
> @@ -403,7 +403,7 @@ enum vmcs_field {
> #define VMX_EPT_EXECUTABLE_MASK 0x4ull
> #define VMX_EPT_IGMT_BIT (1ull << 6)
>
> -#define VMX_EPT_IDENTITY_PAGETABLE_ADDR 0xfffbc000ul
> +#define VMX_EPT_IDENTITY_PAGETABLE_ADDR 0xfeffc000ul
>
>
> #define ASM_VMX_VMCLEAR_RAX ".byte 0x66, 0x0f, 0xc7, 0x30"
> diff --git a/qemu-kvm-x86.c b/qemu-kvm-x86.c
> index daf60b6..b5306aa 100644
> --- a/qemu-kvm-x86.c
> +++ b/qemu-kvm-x86.c
> @@ -63,7 +63,7 @@ static int kvm_init_tss(kvm_context_t kvm)
> * this address is 3 pages before the bios, and the bios should present
> * as unavaible memory
> */
> - r = kvm_set_tss_addr(kvm, 0xfffbd000);
> + r = kvm_set_tss_addr(kvm, 0xfeffd000);
> if (r < 0) {
> fprintf(stderr, "kvm_init_tss: unable to set tss addr\n");
> return r;
--
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