On 08/13/19 13:31, Anthony PERARD wrote:
> When the Xen PVH entry point has been used, hvmloader hasn't run and
> hasn't prepared an E820 table. The only way left to get an E820 table
> is to ask Xen via an hypercall. We keep the result cached to avoid
> making a second hypercall which would give the same result.
>
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1689
> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
> Acked-by: Laszlo Ersek <lersek@redhat.com>
> ---
>
> Notes:
> v5:
> - fix commit message, the hypercall *can* be made several time, but we
> still cache the result.
Addresses Roger's feedback in:
http://mid.mail-archive.com/20190808104558.vm6dfic5dntjsnt4@Air-de-Roger
https://edk2.groups.io/g/devel/message/45160
My ACK stands.
Thanks
Laszlo
> v3:
> - fix commit message
> - add 'm' prefix to the global variables
> and make them static
>
> OvmfPkg/XenPlatformPei/Xen.c | 46 +++++++++++++++++++++++++++++++++++-
> 1 file changed, 45 insertions(+), 1 deletion(-)
>
> diff --git a/OvmfPkg/XenPlatformPei/Xen.c b/OvmfPkg/XenPlatformPei/Xen.c
> index f26f0e56dd..72f6f37b46 100644
> --- a/OvmfPkg/XenPlatformPei/Xen.c
> +++ b/OvmfPkg/XenPlatformPei/Xen.c
> @@ -27,6 +27,7 @@
> #include <Library/MtrrLib.h>
> #include <IndustryStandard/Xen/arch-x86/hvm/start_info.h>
> #include <Library/XenHypercallLib.h>
> +#include <IndustryStandard/Xen/memory.h>
>
> #include "Platform.h"
> #include "Xen.h"
> @@ -40,6 +41,8 @@ EFI_XEN_INFO mXenInfo;
> // Only the E820 table is used by OVMF.
> //
> EFI_XEN_OVMF_INFO *mXenHvmloaderInfo;
> +STATIC EFI_E820_ENTRY64 mE820Entries[128];
> +STATIC UINT32 mE820EntriesCount;
>
> /**
> Returns E820 map provided by Xen
> @@ -55,6 +58,12 @@ XenGetE820Map (
> UINT32 *Count
> )
> {
> + INTN ReturnCode;
> + xen_memory_map_t Parameters;
> + UINTN LoopIndex;
> + UINTN Index;
> + EFI_E820_ENTRY64 TmpEntry;
> +
> //
> // Get E820 produced by hvmloader
> //
> @@ -66,7 +75,42 @@ XenGetE820Map (
> return EFI_SUCCESS;
> }
>
> - return EFI_NOT_FOUND;
> + //
> + // Otherwise, get the E820 table from the Xen hypervisor
> + //
> +
> + if (mE820EntriesCount > 0) {
> + *Entries = mE820Entries;
> + *Count = mE820EntriesCount;
> + return EFI_SUCCESS;
> + }
> +
> + Parameters.nr_entries = 128;
> + set_xen_guest_handle (Parameters.buffer, mE820Entries);
> +
> + // Returns a errno
> + ReturnCode = XenHypercallMemoryOp (XENMEM_memory_map, &Parameters);
> + ASSERT (ReturnCode == 0);
> +
> + mE820EntriesCount = Parameters.nr_entries;
> +
> + //
> + // Sort E820 entries
> + //
> + for (LoopIndex = 1; LoopIndex < mE820EntriesCount; LoopIndex++) {
> + for (Index = LoopIndex; Index < mE820EntriesCount; Index++) {
> + if (mE820Entries[Index - 1].BaseAddr > mE820Entries[Index].BaseAddr) {
> + TmpEntry = mE820Entries[Index];
> + mE820Entries[Index] = mE820Entries[Index - 1];
> + mE820Entries[Index - 1] = TmpEntry;
> + }
> + }
> + }
> +
> + *Count = mE820EntriesCount;
> + *Entries = mE820Entries;
> +
> + return EFI_SUCCESS;
> }
>
> /**
>
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