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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [edk2-devel] [PATCH v2 08/31] OvmfPkg/XenResetVector: Allow to jumpstart from either hvmloader or PVH
On 04/09/19 13:08, Anthony PERARD wrote:
> This patch allows the ResetVector to be run indenpendently from build
> time addresses.
>
> The goal of the patch is to avoid having to create RAM just below 4G
> when creating a Xen PVH guest while been compatible with the way
(1) s/been/being/
> hvmloader currently load OVMF, just below 4G.
>
> Only the new PVH entry point will do the calculation.
>
> The ResetVector will figure out its current running address by creating
> a temporary stack, make a call and calculate the difference between the
> build time address and the address at run time.
>
> This patch copies and make the necessary modification to some other asm
> files:
> - copy of UefiCpuPkg/.../Flat32ToFlat64.asm:
> Allow Transition32FlatTo64Flat to been runnned from anywhere in memory
(2) s/been runned/be run/
> _ copy of UefiCpuPkg/../SearchForBfvBase.asm:
(3) please replace the underscore (_) with a hyphen (-)
> Add a extra parameter to indicate where to start the search for the
> boot firmware volume.
>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
> ---
> OvmfPkg/XenResetVector/Ia16/Real16ToFlat32.asm
> | 3 ++
> {UefiCpuPkg/ResetVector/Vtf0 =>
> OvmfPkg/XenResetVector}/Ia32/Flat32ToFlat64.asm | 25 ++++++++++++++--
> {UefiCpuPkg/ResetVector/Vtf0 =>
> OvmfPkg/XenResetVector}/Ia32/SearchForBfvBase.asm | 19 +++++++++----
> OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm
> | 30 ++++++++++++++++++--
> 4 files changed, 66 insertions(+), 11 deletions(-)
(4) For the subject line: please drop the word "to".
With those:
Acked-by: Laszlo Ersek <lersek@xxxxxxxxxx>
Thanks
Laszlo
>
> diff --git a/OvmfPkg/XenResetVector/Ia16/Real16ToFlat32.asm
> b/OvmfPkg/XenResetVector/Ia16/Real16ToFlat32.asm
> index e22e92c8a6..eebced6ced 100644
> --- a/OvmfPkg/XenResetVector/Ia16/Real16ToFlat32.asm
> +++ b/OvmfPkg/XenResetVector/Ia16/Real16ToFlat32.asm
> @@ -61,6 +61,9 @@ jumpTo32BitAndLandHere:
> mov gs, ax
> mov ss, ax
>
> + ; parameter for Flat32SearchForBfvBase
> + xor eax, eax ; Start searching from top of 4GB for BfvBase
> +
> OneTimeCallRet TransitionFromReal16To32BitFlat
>
> ALIGN 2
> diff --git a/UefiCpuPkg/ResetVector/Vtf0/Ia32/Flat32ToFlat64.asm
> b/OvmfPkg/XenResetVector/Ia32/Flat32ToFlat64.asm
> similarity index 69%
> copy from UefiCpuPkg/ResetVector/Vtf0/Ia32/Flat32ToFlat64.asm
> copy to OvmfPkg/XenResetVector/Ia32/Flat32ToFlat64.asm
> index 5b6b375330..ca03ea43e0 100644
> --- a/UefiCpuPkg/ResetVector/Vtf0/Ia32/Flat32ToFlat64.asm
> +++ b/OvmfPkg/XenResetVector/Ia32/Flat32ToFlat64.asm
> @@ -3,6 +3,8 @@
> ; Transition from 32 bit flat protected mode into 64 bit flat protected mode
> ;
> ; Copyright (c) 2008 - 2018, Intel Corporation. All rights reserved.<BR>
> +; Copyright (c) 2019, Citrix Systems, Inc.
> +;
> ; This program and the accompanying materials
> ; are licensed and made available under the terms and conditions of the BSD
> License
> ; which accompanies this distribution. The full text of the license may be
> found at
> @@ -16,7 +18,7 @@
> BITS 32
>
> ;
> -; Modified: EAX
> +; Modified: EAX, EBX, ECX, EDX, ESP
> ;
> Transition32FlatTo64Flat:
>
> @@ -35,10 +37,29 @@ Transition32FlatTo64Flat:
> bts eax, 31 ; set PG
> mov cr0, eax ; enable paging
>
> - jmp LINEAR_CODE64_SEL:ADDR_OF(jumpTo64BitAndLandHere)
> + ; backup ESP
> + mov ebx, esp
> +
> + ;; recalculate delta
> + mov esp, PVH_SPACE(16)
> + call .delta
> +.delta:
> + pop edx
> + sub edx, ADDR_OF(.delta)
> +
> + ; push return addr and seg to the stack, then return far
> + push dword LINEAR_CODE64_SEL
> + mov eax, ADDR_OF(jumpTo64BitAndLandHere)
> + add eax, edx ; add delta
> + push eax
> + retf
> +
> BITS 64
> jumpTo64BitAndLandHere:
>
> + ; restore ESP
> + mov esp, ebx
> +
> debugShowPostCode POSTCODE_64BIT_MODE
>
> OneTimeCallRet Transition32FlatTo64Flat
> diff --git a/UefiCpuPkg/ResetVector/Vtf0/Ia32/SearchForBfvBase.asm
> b/OvmfPkg/XenResetVector/Ia32/SearchForBfvBase.asm
> similarity index 83%
> copy from UefiCpuPkg/ResetVector/Vtf0/Ia32/SearchForBfvBase.asm
> copy to OvmfPkg/XenResetVector/Ia32/SearchForBfvBase.asm
> index d0c2d8c39c..0519e05601 100644
> --- a/UefiCpuPkg/ResetVector/Vtf0/Ia32/SearchForBfvBase.asm
> +++ b/OvmfPkg/XenResetVector/Ia32/SearchForBfvBase.asm
> @@ -3,6 +3,8 @@
> ; Search for the Boot Firmware Volume (BFV) base address
> ;
> ; Copyright (c) 2008 - 2009, Intel Corporation. All rights reserved.<BR>
> +; Copyright (c) 2019, Citrix Systems, Inc.
> +;
> ; This program and the accompanying materials
> ; are licensed and made available under the terms and conditions of the BSD
> License
> ; which accompanies this distribution. The full text of the license may be
> found at
> @@ -23,22 +25,26 @@
> BITS 32
>
> ;
> -; Modified: EAX, EBX
> +; Modified: EAX, EBX, ECX
> ; Preserved: EDI, ESP
> ;
> +; @param[in] EAX Start search from here
> ; @param[out] EBP Address of Boot Firmware Volume (BFV)
> ;
> Flat32SearchForBfvBase:
>
> - xor eax, eax
> + mov ecx, eax
> searchingForBfvHeaderLoop:
> ;
> - ; We check for a firmware volume at every 4KB address in the top 16MB
> - ; just below 4GB. (Addresses at 0xffHHH000 where H is any hex digit.)
> + ; We check for a firmware volume at every 4KB address in the 16MB
> + ; just below where we started, ECX.
> ;
> sub eax, 0x1000
> - cmp eax, 0xff000000
> - jb searchedForBfvHeaderButNotFound
> + mov ebx, ecx
> + sub ebx, eax
> + cmp ebx, 0x01000000
> + ; if ECX-EAX > 16MB; jump notfound
> + ja searchedForBfvHeaderButNotFound
>
> ;
> ; Check FFS GUID
> @@ -59,6 +65,7 @@ searchingForBfvHeaderLoop:
> jne searchingForBfvHeaderLoop
> mov ebx, eax
> add ebx, dword [eax + 0x20]
> + cmp ebx, ecx
> jnz searchingForBfvHeaderLoop
>
> jmp searchedForBfvHeaderAndItWasFound
> diff --git a/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm
> b/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm
> index 4e55b0ac1f..612b2e9c44 100644
> --- a/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm
> +++ b/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm
> @@ -19,22 +19,39 @@ BITS 32
> xenPVHMain:
> mov di, 'BP'
>
> - ; ESP - Initial value of the EAX register (BIST: Built-in Self Test)
> - mov esp, eax
> + ; EBP - Initial value of the EAX register (BIST: Built-in Self Test)
> + mov ebp, eax
>
> ;; Store "Start of day" struct pointer for later use
> mov dword[PVH_SPACE (0)], ebx
> mov dword[PVH_SPACE (4)], 'XPVH'
>
> + ;; calculate delta between build-addr and run position
> + mov esp, PVH_SPACE(16) ; create a temporary stack
> + call .delta
> +.delta:
> + pop edx ; get addr of .delta
> + sub edx, ADDR_OF(.delta) ; calculate delta
> +
> cli
>
> + ;; Find address of GDT and gdtr and fix the later
> mov ebx, ADDR_OF(gdtr)
> + add ebx, edx ; add delta gdtr
> + mov eax, ADDR_OF(GDT_BASE)
> + add eax, edx ; add delta to GDT_BASE
> + mov dword[ebx + 2], eax ; fix GDT_BASE addr in gdtr
> lgdt [ebx]
>
> mov eax, SEC_DEFAULT_CR0
> mov cr0, eax
>
> - jmp LINEAR_CODE_SEL:ADDR_OF(.jmpToNewCodeSeg)
> + ;; push return addr to the stack, then return far
> + push dword LINEAR_CODE_SEL ; segment to select
> + mov eax, ADDR_OF(.jmpToNewCodeSeg) ; return addr
> + add eax, edx ; add delta to return addr
> + push eax
> + retf
> .jmpToNewCodeSeg:
>
> mov eax, SEC_DEFAULT_CR4
> @@ -47,5 +64,12 @@ xenPVHMain:
> mov gs, ax
> mov ss, ax
>
> + ; ESP - Initial value of the EAX register (BIST: Built-in Self Test)
> + mov esp, ebp
> +
> + ; parameter for Flat32SearchForBfvBase
> + mov eax, ADDR_OF(fourGigabytes)
> + add eax, edx ; add delta
> +
> ; return to the Main16
> OneTimeCallRet TransitionFromReal16To32BitFlat
>
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