| Message ID | 20210211120426.159999-1-igor.opaniuk@gmail.com |
|---|---|
| State | Deferred |
| Delegated to: | Tom Rini |
| Headers | show |
| Series | [v1] qemu-arm: round down memory to multiple of 2MB | expand |
On 11.02.21 13:04, Igor Opaniuk wrote: > From: Igor Opaniuk <igor.opaniuk@foundries.io> > > When LPAE is enabled, 1:1 mapping is created using 2 MB blocks. > In case amount of memory provided to QEMU is not multiple > of 2 MB, round down the amount of available memory to avoid hang > during MMU initialization. > > How to reproduce: > qemu-system-arm -machine virt -m 1058 -nographic -bios u-boot.bin - boots > qemu-system-arm -machine virt -m 1057 -nographic -bios u-boot.bin - hangs > > DRAM: 1 GiB > initcall: 60011df8 > initcall: 60011904 > New Stack Pointer is: 80fffe90 > initcall: 60011a20 > initcall: 60011bcc > initcall: 60011bd4 > initcall: 600119b4 > Relocation Offset is: 22042000 > Relocating to 82042000, new gd at 81001ed0, sp at 80fffe90 > initcall: 60011b8c > initcall: 82053ea0 > initcall: 82053ea8 > initcall: 60012040 (relocated to 82054040) > dram_bank_mmu_setup: bank: 0 > --- hang here during mmu init --- > > Fixes: 3fa914af82("arm: qemu: implement enable_caches()") > Signed-off-by: Igor Opaniuk <igor.opaniuk@foundries.io> > > --- > > board/emulation/qemu-arm/qemu-arm.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/board/emulation/qemu-arm/qemu-arm.c b/board/emulation/qemu-arm/qemu-arm.c > index aa68bef469..841dd7af0e 100644 > --- a/board/emulation/qemu-arm/qemu-arm.c > +++ b/board/emulation/qemu-arm/qemu-arm.c > @@ -84,6 +84,18 @@ int dram_init(void) > if (fdtdec_setup_mem_size_base() != 0) > return -EINVAL; > > + /* > + * When LPAE is enabled (ARMv7), > + * 1:1 mapping is created using 2 MB blocks. > + * > + * In case amount of memory provided to QEMU > + * is not multiple of 2 MB, round down the amount > + * of available memory to avoid hang during MMU > + * initialization. > + */ > + if (CONFIG_IS_ENABLED(ARMV7_LPAE)) > + gd->ram_size -= (gd->ram_size % 0x200000); Is the problem LPAE specific? Couldn't you provoke same problem using an odd memory size without LPAE, e.g qemu-system-arm -m 536870908 (512 MiB - 4)? Best regards Heinrich > + > return 0; > } > >
On Thu, 11 Feb 2021 at 15:18, Heinrich Schuchardt <xypron.glpk@gmx.de> wrote: > > On 11.02.21 13:04, Igor Opaniuk wrote: > > From: Igor Opaniuk <igor.opaniuk@foundries.io> > > > > When LPAE is enabled, 1:1 mapping is created using 2 MB blocks. > > In case amount of memory provided to QEMU is not multiple > > of 2 MB, round down the amount of available memory to avoid hang > > during MMU initialization. > > > > How to reproduce: > > qemu-system-arm -machine virt -m 1058 -nographic -bios u-boot.bin - boots > > qemu-system-arm -machine virt -m 1057 -nographic -bios u-boot.bin - hangs > > > > DRAM: 1 GiB > > initcall: 60011df8 > > initcall: 60011904 > > New Stack Pointer is: 80fffe90 > > initcall: 60011a20 > > initcall: 60011bcc > > initcall: 60011bd4 > > initcall: 600119b4 > > Relocation Offset is: 22042000 > > Relocating to 82042000, new gd at 81001ed0, sp at 80fffe90 > > initcall: 60011b8c > > initcall: 82053ea0 > > initcall: 82053ea8 > > initcall: 60012040 (relocated to 82054040) > > dram_bank_mmu_setup: bank: 0 > > --- hang here during mmu init --- > > > > Fixes: 3fa914af82("arm: qemu: implement enable_caches()") > > Signed-off-by: Igor Opaniuk <igor.opaniuk@foundries.io> > > > > --- > > > > board/emulation/qemu-arm/qemu-arm.c | 12 ++++++++++++ > > 1 file changed, 12 insertions(+) > > > > diff --git a/board/emulation/qemu-arm/qemu-arm.c b/board/emulation/qemu-arm/qemu-arm.c > > index aa68bef469..841dd7af0e 100644 > > --- a/board/emulation/qemu-arm/qemu-arm.c > > +++ b/board/emulation/qemu-arm/qemu-arm.c > > @@ -84,6 +84,18 @@ int dram_init(void) > > if (fdtdec_setup_mem_size_base() != 0) > > return -EINVAL; > > > > + /* > > + * When LPAE is enabled (ARMv7), > > + * 1:1 mapping is created using 2 MB blocks. > > + * > > + * In case amount of memory provided to QEMU > > + * is not multiple of 2 MB, round down the amount > > + * of available memory to avoid hang during MMU > > + * initialization. > > + */ > > + if (CONFIG_IS_ENABLED(ARMV7_LPAE)) > > + gd->ram_size -= (gd->ram_size % 0x200000); > > Is the problem LPAE specific? > Couldn't you provoke same problem using an odd memory size without LPAE, > e.g qemu-system-arm -m 536870908 (512 MiB - 4)? > The above value means 512 GiB - 4 MiB, so that shouldn't be a problem. I don't think QEMU's -m option takes fractional megabyte values.
On 11.02.21 15:56, Ard Biesheuvel wrote: > On Thu, 11 Feb 2021 at 15:18, Heinrich Schuchardt <xypron.glpk@gmx.de> wrote: >> >> On 11.02.21 13:04, Igor Opaniuk wrote: >>> From: Igor Opaniuk <igor.opaniuk@foundries.io> >>> >>> When LPAE is enabled, 1:1 mapping is created using 2 MB blocks. >>> In case amount of memory provided to QEMU is not multiple >>> of 2 MB, round down the amount of available memory to avoid hang >>> during MMU initialization. >>> >>> How to reproduce: >>> qemu-system-arm -machine virt -m 1058 -nographic -bios u-boot.bin - boots >>> qemu-system-arm -machine virt -m 1057 -nographic -bios u-boot.bin - hangs >>> >>> DRAM: 1 GiB >>> initcall: 60011df8 >>> initcall: 60011904 >>> New Stack Pointer is: 80fffe90 >>> initcall: 60011a20 >>> initcall: 60011bcc >>> initcall: 60011bd4 >>> initcall: 600119b4 >>> Relocation Offset is: 22042000 >>> Relocating to 82042000, new gd at 81001ed0, sp at 80fffe90 >>> initcall: 60011b8c >>> initcall: 82053ea0 >>> initcall: 82053ea8 >>> initcall: 60012040 (relocated to 82054040) >>> dram_bank_mmu_setup: bank: 0 >>> --- hang here during mmu init --- >>> >>> Fixes: 3fa914af82("arm: qemu: implement enable_caches()") >>> Signed-off-by: Igor Opaniuk <igor.opaniuk@foundries.io> >>> >>> --- >>> >>> board/emulation/qemu-arm/qemu-arm.c | 12 ++++++++++++ >>> 1 file changed, 12 insertions(+) >>> >>> diff --git a/board/emulation/qemu-arm/qemu-arm.c b/board/emulation/qemu-arm/qemu-arm.c >>> index aa68bef469..841dd7af0e 100644 >>> --- a/board/emulation/qemu-arm/qemu-arm.c >>> +++ b/board/emulation/qemu-arm/qemu-arm.c >>> @@ -84,6 +84,18 @@ int dram_init(void) >>> if (fdtdec_setup_mem_size_base() != 0) >>> return -EINVAL; >>> >>> + /* >>> + * When LPAE is enabled (ARMv7), >>> + * 1:1 mapping is created using 2 MB blocks. >>> + * >>> + * In case amount of memory provided to QEMU >>> + * is not multiple of 2 MB, round down the amount >>> + * of available memory to avoid hang during MMU >>> + * initialization. >>> + */ >>> + if (CONFIG_IS_ENABLED(ARMV7_LPAE)) >>> + gd->ram_size -= (gd->ram_size % 0x200000); >> >> Is the problem LPAE specific? >> Couldn't you provoke same problem using an odd memory size without LPAE, >> e.g qemu-system-arm -m 536870908 (512 MiB - 4)? >> > > The above value means 512 GiB - 4 MiB, so that shouldn't be a problem. > I don't think QEMU's -m option takes fractional megabyte values. > $ qemu-system-arm -machine virt -cpu cortex-a15 -m 100005k \ -bios denx/u-boot.bin -nographic => fdt addr $fdt_addr => fdt print /memory@40000000 memory@40000000 { reg = <0x00000000 0x40000000 0x00000000 0x061aa000>; device_type = "memory"; }; Granularity seems to be 0x2000 = 8 KiB. Best regards Heinrich
On Thu, 11 Feb 2021 at 16:34, Heinrich Schuchardt <xypron.glpk@gmx.de> wrote: > > On 11.02.21 15:56, Ard Biesheuvel wrote: > > On Thu, 11 Feb 2021 at 15:18, Heinrich Schuchardt <xypron.glpk@gmx.de> wrote: > >> > >> On 11.02.21 13:04, Igor Opaniuk wrote: > >>> From: Igor Opaniuk <igor.opaniuk@foundries.io> > >>> > >>> When LPAE is enabled, 1:1 mapping is created using 2 MB blocks. > >>> In case amount of memory provided to QEMU is not multiple > >>> of 2 MB, round down the amount of available memory to avoid hang > >>> during MMU initialization. > >>> > >>> How to reproduce: > >>> qemu-system-arm -machine virt -m 1058 -nographic -bios u-boot.bin - boots > >>> qemu-system-arm -machine virt -m 1057 -nographic -bios u-boot.bin - hangs > >>> > >>> DRAM: 1 GiB > >>> initcall: 60011df8 > >>> initcall: 60011904 > >>> New Stack Pointer is: 80fffe90 > >>> initcall: 60011a20 > >>> initcall: 60011bcc > >>> initcall: 60011bd4 > >>> initcall: 600119b4 > >>> Relocation Offset is: 22042000 > >>> Relocating to 82042000, new gd at 81001ed0, sp at 80fffe90 > >>> initcall: 60011b8c > >>> initcall: 82053ea0 > >>> initcall: 82053ea8 > >>> initcall: 60012040 (relocated to 82054040) > >>> dram_bank_mmu_setup: bank: 0 > >>> --- hang here during mmu init --- > >>> > >>> Fixes: 3fa914af82("arm: qemu: implement enable_caches()") > >>> Signed-off-by: Igor Opaniuk <igor.opaniuk@foundries.io> > >>> > >>> --- > >>> > >>> board/emulation/qemu-arm/qemu-arm.c | 12 ++++++++++++ > >>> 1 file changed, 12 insertions(+) > >>> > >>> diff --git a/board/emulation/qemu-arm/qemu-arm.c b/board/emulation/qemu-arm/qemu-arm.c > >>> index aa68bef469..841dd7af0e 100644 > >>> --- a/board/emulation/qemu-arm/qemu-arm.c > >>> +++ b/board/emulation/qemu-arm/qemu-arm.c > >>> @@ -84,6 +84,18 @@ int dram_init(void) > >>> if (fdtdec_setup_mem_size_base() != 0) > >>> return -EINVAL; > >>> > >>> + /* > >>> + * When LPAE is enabled (ARMv7), > >>> + * 1:1 mapping is created using 2 MB blocks. > >>> + * > >>> + * In case amount of memory provided to QEMU > >>> + * is not multiple of 2 MB, round down the amount > >>> + * of available memory to avoid hang during MMU > >>> + * initialization. > >>> + */ > >>> + if (CONFIG_IS_ENABLED(ARMV7_LPAE)) > >>> + gd->ram_size -= (gd->ram_size % 0x200000); > >> > >> Is the problem LPAE specific? > >> Couldn't you provoke same problem using an odd memory size without LPAE, > >> e.g qemu-system-arm -m 536870908 (512 MiB - 4)? > >> > > > > The above value means 512 GiB - 4 MiB, so that shouldn't be a problem. > > I don't think QEMU's -m option takes fractional megabyte values. > > > > $ qemu-system-arm -machine virt -cpu cortex-a15 -m 100005k \ > -bios denx/u-boot.bin -nographic > > => fdt addr $fdt_addr > => fdt print /memory@40000000 > memory@40000000 { > reg = <0x00000000 0x40000000 0x00000000 0x061aa000>; > device_type = "memory"; > }; > > Granularity seems to be 0x2000 = 8 KiB. > In that case, it seems easiest to me to always round down to the nearest multiple of 2MB
Hi Heinrich, On Thu, Feb 11, 2021 at 5:34 PM Heinrich Schuchardt <xypron.glpk@gmx.de> wrote: > > On 11.02.21 15:56, Ard Biesheuvel wrote: > > On Thu, 11 Feb 2021 at 15:18, Heinrich Schuchardt <xypron.glpk@gmx.de> wrote: > >> > >> On 11.02.21 13:04, Igor Opaniuk wrote: > >>> From: Igor Opaniuk <igor.opaniuk@foundries.io> > >>> > >>> When LPAE is enabled, 1:1 mapping is created using 2 MB blocks. > >>> In case amount of memory provided to QEMU is not multiple > >>> of 2 MB, round down the amount of available memory to avoid hang > >>> during MMU initialization. > >>> > >>> How to reproduce: > >>> qemu-system-arm -machine virt -m 1058 -nographic -bios u-boot.bin - boots > >>> qemu-system-arm -machine virt -m 1057 -nographic -bios u-boot.bin - hangs > >>> > >>> DRAM: 1 GiB > >>> initcall: 60011df8 > >>> initcall: 60011904 > >>> New Stack Pointer is: 80fffe90 > >>> initcall: 60011a20 > >>> initcall: 60011bcc > >>> initcall: 60011bd4 > >>> initcall: 600119b4 > >>> Relocation Offset is: 22042000 > >>> Relocating to 82042000, new gd at 81001ed0, sp at 80fffe90 > >>> initcall: 60011b8c > >>> initcall: 82053ea0 > >>> initcall: 82053ea8 > >>> initcall: 60012040 (relocated to 82054040) > >>> dram_bank_mmu_setup: bank: 0 > >>> --- hang here during mmu init --- > >>> > >>> Fixes: 3fa914af82("arm: qemu: implement enable_caches()") > >>> Signed-off-by: Igor Opaniuk <igor.opaniuk@foundries.io> > >>> > >>> --- > >>> > >>> board/emulation/qemu-arm/qemu-arm.c | 12 ++++++++++++ > >>> 1 file changed, 12 insertions(+) > >>> > >>> diff --git a/board/emulation/qemu-arm/qemu-arm.c b/board/emulation/qemu-arm/qemu-arm.c > >>> index aa68bef469..841dd7af0e 100644 > >>> --- a/board/emulation/qemu-arm/qemu-arm.c > >>> +++ b/board/emulation/qemu-arm/qemu-arm.c > >>> @@ -84,6 +84,18 @@ int dram_init(void) > >>> if (fdtdec_setup_mem_size_base() != 0) > >>> return -EINVAL; > >>> > >>> + /* > >>> + * When LPAE is enabled (ARMv7), > >>> + * 1:1 mapping is created using 2 MB blocks. > >>> + * > >>> + * In case amount of memory provided to QEMU > >>> + * is not multiple of 2 MB, round down the amount > >>> + * of available memory to avoid hang during MMU > >>> + * initialization. > >>> + */ > >>> + if (CONFIG_IS_ENABLED(ARMV7_LPAE)) > >>> + gd->ram_size -= (gd->ram_size % 0x200000); > >> > >> Is the problem LPAE specific? > >> Couldn't you provoke same problem using an odd memory size without LPAE, > >> e.g qemu-system-arm -m 536870908 (512 MiB - 4)? > >> > > > > The above value means 512 GiB - 4 MiB, so that shouldn't be a problem. > > I don't think QEMU's -m option takes fractional megabyte values. > > > > $ qemu-system-arm -machine virt -cpu cortex-a15 -m 100005k \ > -bios denx/u-boot.bin -nographic > > => fdt addr $fdt_addr > => fdt print /memory@40000000 > memory@40000000 { > reg = <0x00000000 0x40000000 0x00000000 0x061aa000>; > device_type = "memory"; > }; > > Granularity seems to be 0x2000 = 8 KiB. I've just run some tests (including the mem=100005k ) with LPAE disabled and haven't faced any issues: $ cat .config | grep LPAE # CONFIG_ARMV7_LPAE is not set $ qemu-system-arm -machine virt -m 1057 -nographic -bios u-boot.bin U-Boot 2021.04-rc1-01218-g85e959f09c-dirty (Feb 11 2021 - 17:31:31 +0200) DRAM: 1 GiB Flash: 128 MiB ... => $ qemu-system-arm -machine virt -m 1058 -nographic -bios u-boot.bin U-Boot 2021.04-rc1-01218-g85e959f09c-dirty (Feb 11 2021 - 17:31:31 +0200) DRAM: 1 GiB Flash: 128 MiB ... => $ qemu-system-arm -machine virt -m 100005k -nographic -bios u-boot.bin U-Boot 2021.04-rc1-01218-g85e959f09c-dirty (Feb 11 2021 - 17:31:31 +0200) DRAM: 97.7 MiB Flash: 128 MiB ... => > > Best regards > > Heinrich Regards, Igor
Hello Ard, Just a quick follow-up for this old thread, I've again stumbled upon the same issue recently and it turned out that I've already sent a fix for that here :) Considering Heinrich's comment about memory granularity, does it still make sense to land this patch? If not, what objections/suggestions do you have in mind? Thanks! Regards, Igor On Thu, Feb 11, 2021 at 4:39 PM Igor Opaniuk <igor.opaniuk@foundries.io> wrote: > > Hi Heinrich, > > On Thu, Feb 11, 2021 at 5:34 PM Heinrich Schuchardt <xypron.glpk@gmx.de> wrote: > > > > On 11.02.21 15:56, Ard Biesheuvel wrote: > > > On Thu, 11 Feb 2021 at 15:18, Heinrich Schuchardt <xypron.glpk@gmx.de> wrote: > > >> > > >> On 11.02.21 13:04, Igor Opaniuk wrote: > > >>> From: Igor Opaniuk <igor.opaniuk@foundries.io> > > >>> > > >>> When LPAE is enabled, 1:1 mapping is created using 2 MB blocks. > > >>> In case amount of memory provided to QEMU is not multiple > > >>> of 2 MB, round down the amount of available memory to avoid hang > > >>> during MMU initialization. > > >>> > > >>> How to reproduce: > > >>> qemu-system-arm -machine virt -m 1058 -nographic -bios u-boot.bin - boots > > >>> qemu-system-arm -machine virt -m 1057 -nographic -bios u-boot.bin - hangs > > >>> > > >>> DRAM: 1 GiB > > >>> initcall: 60011df8 > > >>> initcall: 60011904 > > >>> New Stack Pointer is: 80fffe90 > > >>> initcall: 60011a20 > > >>> initcall: 60011bcc > > >>> initcall: 60011bd4 > > >>> initcall: 600119b4 > > >>> Relocation Offset is: 22042000 > > >>> Relocating to 82042000, new gd at 81001ed0, sp at 80fffe90 > > >>> initcall: 60011b8c > > >>> initcall: 82053ea0 > > >>> initcall: 82053ea8 > > >>> initcall: 60012040 (relocated to 82054040) > > >>> dram_bank_mmu_setup: bank: 0 > > >>> --- hang here during mmu init --- > > >>> > > >>> Fixes: 3fa914af82("arm: qemu: implement enable_caches()") > > >>> Signed-off-by: Igor Opaniuk <igor.opaniuk@foundries.io> > > >>> > > >>> --- > > >>> > > >>> board/emulation/qemu-arm/qemu-arm.c | 12 ++++++++++++ > > >>> 1 file changed, 12 insertions(+) > > >>> > > >>> diff --git a/board/emulation/qemu-arm/qemu-arm.c b/board/emulation/qemu-arm/qemu-arm.c > > >>> index aa68bef469..841dd7af0e 100644 > > >>> --- a/board/emulation/qemu-arm/qemu-arm.c > > >>> +++ b/board/emulation/qemu-arm/qemu-arm.c > > >>> @@ -84,6 +84,18 @@ int dram_init(void) > > >>> if (fdtdec_setup_mem_size_base() != 0) > > >>> return -EINVAL; > > >>> > > >>> + /* > > >>> + * When LPAE is enabled (ARMv7), > > >>> + * 1:1 mapping is created using 2 MB blocks. > > >>> + * > > >>> + * In case amount of memory provided to QEMU > > >>> + * is not multiple of 2 MB, round down the amount > > >>> + * of available memory to avoid hang during MMU > > >>> + * initialization. > > >>> + */ > > >>> + if (CONFIG_IS_ENABLED(ARMV7_LPAE)) > > >>> + gd->ram_size -= (gd->ram_size % 0x200000); > > >> > > >> Is the problem LPAE specific? > > >> Couldn't you provoke same problem using an odd memory size without LPAE, > > >> e.g qemu-system-arm -m 536870908 (512 MiB - 4)? > > >> > > > > > > The above value means 512 GiB - 4 MiB, so that shouldn't be a problem. > > > I don't think QEMU's -m option takes fractional megabyte values. > > > > > > > $ qemu-system-arm -machine virt -cpu cortex-a15 -m 100005k \ > > -bios denx/u-boot.bin -nographic > > > > => fdt addr $fdt_addr > > => fdt print /memory@40000000 > > memory@40000000 { > > reg = <0x00000000 0x40000000 0x00000000 0x061aa000>; > > device_type = "memory"; > > }; > > > > Granularity seems to be 0x2000 = 8 KiB. > I've just run some tests (including the mem=100005k ) with LPAE disabled > and haven't faced any issues: > > $ cat .config | grep LPAE > # CONFIG_ARMV7_LPAE is not set > > $ qemu-system-arm -machine virt -m 1057 -nographic -bios u-boot.bin > U-Boot 2021.04-rc1-01218-g85e959f09c-dirty (Feb 11 2021 - 17:31:31 +0200) > > DRAM: 1 GiB > Flash: 128 MiB > ... > => > > $ qemu-system-arm -machine virt -m 1058 -nographic -bios u-boot.bin > > U-Boot 2021.04-rc1-01218-g85e959f09c-dirty (Feb 11 2021 - 17:31:31 +0200) > > DRAM: 1 GiB > Flash: 128 MiB > ... > => > > $ qemu-system-arm -machine virt -m 100005k -nographic -bios u-boot.bin > > U-Boot 2021.04-rc1-01218-g85e959f09c-dirty (Feb 11 2021 - 17:31:31 +0200) > DRAM: 97.7 MiB > Flash: 128 MiB > ... > => > > > > > Best regards > > > > Heinrich > > Regards, > Igor > > -- > Best regards - Freundliche Grüsse - Meilleures salutations > > Igor Opaniuk > Embedded Software Engineer > T: +380 938364067 > E: igor.opaniuk@foundries.io > W: www.foundries.io
diff --git a/board/emulation/qemu-arm/qemu-arm.c b/board/emulation/qemu-arm/qemu-arm.c index aa68bef469..841dd7af0e 100644 --- a/board/emulation/qemu-arm/qemu-arm.c +++ b/board/emulation/qemu-arm/qemu-arm.c @@ -84,6 +84,18 @@ int dram_init(void) if (fdtdec_setup_mem_size_base() != 0) return -EINVAL; + /* + * When LPAE is enabled (ARMv7), + * 1:1 mapping is created using 2 MB blocks. + * + * In case amount of memory provided to QEMU + * is not multiple of 2 MB, round down the amount + * of available memory to avoid hang during MMU + * initialization. + */ + if (CONFIG_IS_ENABLED(ARMV7_LPAE)) + gd->ram_size -= (gd->ram_size % 0x200000); + return 0; }