RE: [PATCH 2/2] x86, efi: Add "efi_fake_mem_mirror" boot option

From: Izumi, Taku
Date: Wed Aug 26 2015 - 04:21:59 EST

Dear Matt,

Thank you for reviewing.

I updated my patchset.
I'm happy if you review new one.

Sincerely,
Taku Izumi

> -----Original Message-----
> From: Matt Fleming [mailto:matt@xxxxxxxxxxxxxxxxxxx]
> Sent: Wednesday, August 26, 2015 8:46 AM
> To: Izumi, Taku/泉 拓
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-efi@xxxxxxxxxxxxxxx; x86@xxxxxxxxxx; matt.fleming@xxxxxxxxx;
> tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; hpa@xxxxxxxxx; tony.luck@xxxxxxxxx; qiuxishi@xxxxxxxxxx; Kamezawa, Hiroyuki/亀
> 澤 寛之
> Subject: Re: [PATCH 2/2] x86, efi: Add "efi_fake_mem_mirror" boot option
>
> On Fri, 21 Aug, at 02:16:00AM, Taku Izumi wrote:
> > This patch introduces new boot option named "efi_fake_mem_mirror".
> > By specifying this parameter, you can mark specific memory as
> > mirrored memory. This is useful for debugging of Address Range
> > Mirroring feature.
> >
> > For example, if you specify "efi_fake_mem_mirror=2G@4G,2G@0x10a0000000",
> > the original (firmware provided) EFI memmap will be updated so that
> > the specified memory regions have EFI_MEMORY_MORE_RELIABLE attribute:
> >
> > <original EFI memmap>
> > efi: mem00: [Boot Data | | | | | | |WB|WT|WC|UC] range=[0x0000000000000000-0x0000000000001000)
> (0MB)
> > efi: mem01: [Loader Data | | | | | | |WB|WT|WC|UC] range=[0x0000000000001000-0x0000000000002000)
> (0MB)
> > ...
> > efi: mem35: [Boot Data | | | | | | |WB|WT|WC|UC] range=[0x0000000047ee6000-0x0000000048014000)
> (1MB)
> > efi: mem36: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000000100000000-0x00000020a0000000)
> (129536MB)
> > efi: mem37: [Reserved |RUN| | | | | | | | |UC] range=[0x0000000060000000-0x0000000090000000)
> (768MB)
> >
> > <updated EFI memmap>
> > efi: mem00: [Boot Data | | | | | | |WB|WT|WC|UC] range=[0x0000000000000000-0x0000000000001000)
> (0MB)
> > efi: mem01: [Loader Data | | | | | | |WB|WT|WC|UC] range=[0x0000000000001000-0x0000000000002000)
> (0MB)
> > ...
> > efi: mem35: [Boot Data | | | | | | |WB|WT|WC|UC] range=[0x0000000047ee6000-0x0000000048014000)
> (1MB)
> > efi: mem36: [Conventional Memory| |RELY| | | | |WB|WT|WC|UC] range=[0x0000000100000000-0x0000000180000000)
> (2048MB)
> > efi: mem37: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000000180000000-0x00000010a0000000)
> (61952MB)
> > efi: mem38: [Conventional Memory| |RELY| | | | |WB|WT|WC|UC] range=[0x00000010a0000000-0x0000001120000000)
> (2048MB)
> > efi: mem39: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000001120000000-0x00000020a0000000)
> (63488MB)
> > efi: mem40: [Reserved |RUN| | | | | | | | |UC] range=[0x0000000060000000-0x0000000090000000)
> (768MB)
> >
> > And you will find that the following message is output:
> >
> > efi: Memory: 4096M/131455M mirrored memory
> >
> > Signed-off-by: Taku Izumi <izumi.taku@xxxxxxxxxxxxxx>
> > ---
> > Documentation/kernel-parameters.txt | 8 ++
> > arch/x86/include/asm/efi.h | 2 +
> > arch/x86/kernel/setup.c | 4 +-
> > arch/x86/platform/efi/efi.c | 2 +-
> > arch/x86/platform/efi/quirks.c | 169 ++++++++++++++++++++++++++++++++++++
> > 5 files changed, 183 insertions(+), 2 deletions(-)
>
> [...]
>
> > diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
> > index 1c7380d..5c785e1 100644
> > --- a/arch/x86/platform/efi/quirks.c
> > +++ b/arch/x86/platform/efi/quirks.c
> > @@ -18,6 +18,10 @@
> >
>
> The quirks file isn't intended to be used for this kind of feature.
> It's very much a repository for workarounds for quirky firmware, i.e.
> known bugs.
>
> Instead, how about putting all this into a new fake_mem.c file? Going
> further than that, there's nothing that I can see that looks
> particularly x86-specific, so how about sticking all this in
> drivers/firmware/efi/fake_mem.c so that the arm64 folks can make use
> of it if/when they want to start playing around with
> EFI_MEMORY_MORE_RELIABLE?
>
> > static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 };
> >
> > +#define EFI_MAX_FAKE_MIRROR 8
> > +static struct range fake_mirrors[EFI_MAX_FAKE_MIRROR];
> > +static int num_fake_mirror;
> > +
> > static bool efi_no_storage_paranoia;
> >
> > /*
> > @@ -288,3 +292,168 @@ bool efi_poweroff_required(void)
> > {
> > return !!acpi_gbl_reduced_hardware;
> > }
> > +
> > +void __init efi_fake_memmap(void)
> > +{
> > + efi_memory_desc_t *md;
> > + void *p, *q;
> > + int i;
> > + int nr_map = memmap.nr_map;
> > + u64 start, end, m_start, m_end;
> > + u64 new_memmap_phy;
> > + void *new_memmap;
> > +
> > + if (!num_fake_mirror)
> > + return;
> > +
> > + /* count up the number of EFI memory descriptor */
> > + for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> > + md = p;
> > + start = md->phys_addr;
> > + end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1;
> > +
> > + for (i = 0; i < num_fake_mirror; i++) {
> > + /* mirroring range */
> > + m_start = fake_mirrors[i].start;
> > + m_end = fake_mirrors[i].end;
> > +
> > + if (m_start <= start) {
> > + /* split into 2 parts */
> > + if (start < m_end && m_end < end)
> > + nr_map++;
> > + }
> > + if (start < m_start && m_start < end) {
> > + /* split into 3 parts */
> > + if (m_end < end)
> > + nr_map += 2;
> > + /* split into 2 parts */
> > + if (end <= m_end)
> > + nr_map++;
> > + }
> > + }
> > + }
> > +
> > + /* allocate memory for new EFI memmap */
> > + new_memmap_phy = memblock_alloc(memmap.desc_size * nr_map, PAGE_SIZE);
> > + if (!new_memmap_phy)
> > + return;
> > +
> > + /* create new EFI memmap */
> > + new_memmap = early_memremap(new_memmap_phy, memmap.desc_size * nr_map);
> > + for (p = memmap.map, q = new_memmap;
> > + p < memmap.map_end;
> > + p += memmap.desc_size, q += memmap.desc_size) {
>
> Can we rename 'p' and 'q', 'old' and 'new'? Otherwise it gets a little
> tricky to follow the below code.
>
>
> --
> Matt Fleming, Intel Open Source Technology Center
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