|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v7 00/14] arm/mem_access: Walk guest page tables in SW if mem_access is active
On 18/07/17 13:24, Sergej Proskurin wrote:
> Hi all,
Hi,
>
> The function p2m_mem_access_check_and_get_page is called from the function
> get_page_from_gva if mem_access is active and the hardware-aided translation
> of
> the given guest virtual address (gva) into machine address fails. That is, if
> the stage-2 translation tables constrain access to the guests's page tables,
> hardware-assisted translation will fail. The idea of the function
> p2m_mem_access_check_and_get_page is thus to translate the given gva and check
> the requested access rights in software. However, as the current
> implementation
> of p2m_mem_access_check_and_get_page makes use of the hardware-aided gva to
> ipa
> translation, the translation might also fail because of reasons stated above
> and will become equally relevant for the altp2m implementation on ARM. As
> such, we provide a software guest translation table walk to address the above
> mentioned issue.
>
> The current version of the implementation supports translation of both the
> short-descriptor as well as the long-descriptor translation table format on
> ARMv7 and ARMv8 (AArch32/AArch64).
>
> This revised version incorporates the comments of the previous patch series.
> In
> this patch version we refine the definition of PAGE_SIZE_GRAN and
> PAGE_MASK_GRAN. In particular, we use PAGE_SIZE_GRAN to define PAGE_MASK_GRAN
> and thus avoid these defines to have a differing type. We also changed the
> previously introduced macro BITS_PER_LONG_LONG to BITS_PER_LLONG. Further
> changes comprise minor adjustments in comments and renaming of macros and
> function parameters. Some additional changes comprising code readability and
> correct type usage have been made and stated in the individual commits.
>
> The following patch series can be found on Github[0].
I tried this series today with the change [1] in Xen to check the translation
is valid. However, I got a failure when booting non-LPAE arm32 Dom0:
(XEN) Loading kernel from boot module @ 0000000080008000
(XEN) Allocating 1:1 mappings totalling 512MB for dom0:
(XEN) BANK[0] 0x000000a0000000-0x000000c0000000 (512MB)
(XEN) Grant table range: 0x000000ffe00000-0x000000ffe6a000
(XEN) Loading zImage from 0000000080008000 to 00000000a7800000-00000000a7f50e28
(XEN) Allocating PPI 16 for event channel interrupt
(XEN) Loading dom0 DTB to 0x00000000a8000000-0x00000000a8001f8e
(XEN) Std. Loglevel: All
(XEN) Guest Loglevel: All
(XEN) guest_walk_tables: gva 0xffeff018 pipa 0x1c090018
(XEN) access_guest_memory_by_ipa: gpa 0xa0207ff8
(XEN) access_guest_memory_by_ipa: gpa 0xffffffffa13aebfc
(XEN) d0: guestcopy: failed to get table entry.
(XEN) Xen BUG at traps.c:2737
(XEN) ----[ Xen-4.10-unstable arm32 debug=y Not tainted ]----
(XEN) CPU: 0
(XEN) PC: 00264dc0 do_trap_guest_sync+0x161c/0x1804
(XEN) CPSR: a000005a MODE:Hypervisor
(XEN) R0: ffffffea R1: 00000000 R2: 00000000 R3: 0000004a
(XEN) R4: 93830007 R5: 47fcff58 R6: 93830007 R7: 00000007
(XEN) R8: 1c090000 R9: 00000000 R10:00000000 R11:47fcff54 R12:ffffffea
(XEN) HYP: SP: 47fcfee4 LR: 00258dec
(XEN)
(XEN) VTCR_EL2: 80003558
(XEN) VTTBR_EL2: 00010008f3ffc000
(XEN)
(XEN) SCTLR_EL2: 30cd187f
(XEN) HCR_EL2: 000000000038663f
(XEN) TTBR0_EL2: 00000000fff02000
(XEN)
(XEN) ESR_EL2: 00000000
(XEN) HPFAR_EL2: 00000000001c0900
(XEN) HDFAR: ffeff018
(XEN) HIFAR: 00000000
(XEN)
(XEN) Xen stack trace from sp=47fcfee4:
(XEN) 00000000 47fcff34 00256008 47fcfefc 47fcfefc 200000da 00000004 47fd48f4
(XEN) 002d5ef0 00000004 002d1f00 00000004 00000000 002d1f00 c163f740 93830007
(XEN) ffeff018 1c090018 00000000 47fcff44 c15e70ac 0000005b c15e70ac c074400c
(XEN) 00000031 00000000 c0743ff8 47fcff58 00268ce0 c15e70ac 0000005b 00000031
(XEN) ffeff000 c15e70ac 0000005b c15e70ac c074400c 00000031 00000000 c0743ff8
(XEN) 00000000 0000001f ffffffff 00000000 c074401c 200001d3 93830007 00000000
(XEN) c161cac0 c161cac0 c1501de0 c0735640 c161cacc c161cacc c161cad8 c161cad8
(XEN) 00000000 00000000 00000000 00000000 00000000 c161cae4 c161cae4 400001d3
(XEN) 00000000 00000000 00000000 00000000 00000000 dfdfdfcf cfdfdfdf
(XEN) Xen call trace:
(XEN) [<00264dc0>] do_trap_guest_sync+0x161c/0x1804 (PC)
(XEN) [<00258dec>] access_guest_memory_by_ipa+0x25c/0x284 (LR)
(XEN) [<00268ce0>] entry.o#return_from_trap+0/0x4
(XEN)
(XEN)
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) Xen BUG at traps.c:2737
(XEN) ****************************************
(XEN)
(XEN) Reboot in five seconds...
The IPA 0xffffffffa13aebfc is not valid for the domain.
Cheers,
[1]
diff --git a/xen/arch/arm/guestcopy.c b/xen/arch/arm/guestcopy.c
index 4ee07fcea3..89c5ebf3cf 100644
--- a/xen/arch/arm/guestcopy.c
+++ b/xen/arch/arm/guestcopy.c
@@ -139,6 +139,8 @@ int access_guest_memory_by_ipa(struct domain *d, paddr_t
gpa, void *buf,
return -EINVAL;
}
+ printk("%s: gpa 0x%llx\n", __FUNCTION__, gpa);
+
page = get_page_from_gfn(d, paddr_to_pfn(gpa), &p2mt, P2M_ALLOC);
if ( !page )
{
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index c07999b518..904abafcae 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2688,6 +2688,8 @@ static bool try_map_mmio(gfn_t gfn)
return !map_regions_p2mt(d, gfn, 1, mfn, p2m_mmio_direct_c);
}
+#include <asm/guest_walk.h>
+
static void do_trap_data_abort_guest(struct cpu_user_regs *regs,
const union hsr hsr)
{
@@ -2725,6 +2727,17 @@ static void do_trap_data_abort_guest(struct
cpu_user_regs *regs,
return; /* Try again */
}
+ {
+ paddr_t ipa, pipa;
+ rc = gva_to_ipa(info.gva, &info.ipa, GV2M_READ);
+ BUG_ON(rc);
+ printk("guest_walk_tables: gva 0x%x pipa 0x%llx\n",
+ info.gva, pipa);
+ rc = guest_walk_tables(current, info.gva, &ipa, NULL);
+ BUG_ON(rc);
+ BUG_ON(ipa != pipa);
+ }
+
switch ( fsc )
{
case FSC_FLT_PERM:
>
> Cheers,
> ~Sergej
>
> [0] https://github.com/sergej-proskurin/xen (branch arm-gpt-walk-v7)
>
> Sergej Proskurin (14):
> arm/mem_access: Add and cleanup (TCR_|TTBCR_)* defines
> arm/mem_access: Move PAGE_*_* macros to xen/page-defs.h
> arm/mem_access: Add defines supporting PTs with varying page sizes
> arm/lpae: Introduce lpae_is_page helper
> arm/mem_access: Add short-descriptor pte typedefs and macros
> arm/mem_access: Introduce GV2M_EXEC permission
> arm/mem_access: Introduce BIT_ULL bit operation
> arm/mem_access: Introduce GENMASK_ULL bit operation
> arm/guest_access: Move vgic_access_guest_memory to guest_access.h
> arm/guest_access: Rename vgic_access_guest_memory
> arm/mem_access: Add software guest-page-table walk
> arm/mem_access: Add long-descriptor based gpt
> arm/mem_access: Add short-descriptor based gpt
> arm/mem_access: Walk the guest's pt in software
>
> xen/arch/arm/Makefile | 1 +
> xen/arch/arm/guest_walk.c | 631
> +++++++++++++++++++++++++++++++++++++
> xen/arch/arm/guestcopy.c | 50 +++
> xen/arch/arm/mem_access.c | 31 +-
> xen/arch/arm/vgic-v3-its.c | 37 +--
> xen/arch/arm/vgic.c | 49 ---
> xen/include/asm-arm/bitops.h | 1 +
> xen/include/asm-arm/config.h | 2 +
> xen/include/asm-arm/guest_access.h | 3 +
> xen/include/asm-arm/guest_walk.h | 19 ++
> xen/include/asm-arm/lpae.h | 66 ++++
> xen/include/asm-arm/page.h | 1 +
> xen/include/asm-arm/processor.h | 69 +++-
> xen/include/asm-arm/short-desc.h | 130 ++++++++
> xen/include/asm-arm/vgic.h | 3 -
> xen/include/asm-x86/config.h | 2 +
> xen/include/xen/bitops.h | 3 +
> xen/include/xen/iommu.h | 15 +-
> xen/include/xen/page-defs.h | 24 ++
> 19 files changed, 1048 insertions(+), 89 deletions(-)
> create mode 100644 xen/arch/arm/guest_walk.c
> create mode 100644 xen/include/asm-arm/guest_walk.h
> create mode 100644 xen/include/asm-arm/short-desc.h
> create mode 100644 xen/include/xen/page-defs.h
>
> --
> 2.13.2
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> https://lists.xen.org/xen-devel
>
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |