From: "Jan Beulich" <JBeulich@suse.com>
To: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
David Vrabel <david.vrabel@citrix.com>,
xen-devel@lists.xenproject.org,
Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [PATCH v3 07/32] xen/x86: fix arch_set_info_guest for HVM guests
Date: Fri, 24 Jul 2015 09:49:31 -0600 [thread overview]
Message-ID: <55B27AAB02000078000954A0@prv-mh.provo.novell.com> (raw)
In-Reply-To: <55B25941.9@citrix.com>
>>> On 24.07.15 at 17:26, <roger.pau@citrix.com> wrote:
> El 24/07/15 a les 14.44, Jan Beulich ha escrit:
>>>>> On 24.07.15 at 14:11, <roger.pau@citrix.com> wrote:
>>> Or your idea was to put all the bitness specific registers inside of
>>> another separate structure and then unionize them? AFAICT the 16 and
>>> 32bit structures are going to be empty.
>>
>> How that? 64-bit mode e.g. doesn't need full descriptor data for
>> many of the segment registers.
>
> Please bear with me, but AFAIK cs, ds, es and ss still need to point to
> a GDT entry with a 0 base and a limit of 2^64.
No, in 64-bit mode bases are implicitly zero (with the exception of
fs and gs) and limits are implicitly 2^64-1 (which you can't even
express in a descriptor table entry, and with the exception of AMD's
Long Mode Segment Limit extension).
But looking at the code below I see that you're thinking of selector
values only, which would imply that you expect the hypervisor
to actually read descriptors from the descriptor tables. That's
doable, but cumbersome.
> What about the following layout:
>
> #if defined(__GNUC__) && !defined(__STRICT_ANSI__)
> /* Anonymous union includes 16-, 32- and 64-bit names (e.g., bp/ebp/rbp). */
> # define __DECL_REG(n64, n32, n16) union { \
> uint64_t n64; \
> uint32_t n32; \
> uint16_t n16; \
> }
> #else
> /* Non-gcc sources must always use the proper 64-bit name (e.g., rbp). */
> #define __DECL_REG(n64, n32, n16) uint64_t n64
> #endif
Since you keep repeating this, I finally have to comment on it: This
is a suitable model for where we use it currently. It's imo not
suitable at all here - not the least because even non-gcc users
should be allowed to use just a 32-bit field when they mean one.
But the problem is also that for 16- and 32-bit mode a 64-bit
register is meaningless: Equally well you could expose r8-r15 to
them.
> #define __DECL_GP_REG(n) __DECL_REG(r##n, e##n, n)
>
> struct cpu_x86_16 {
> /* Control registers. */
> uint32_t cr[8];
> /* Debug registers. */
> uint32_t dr[8];
> /* GDT descriptor address. */
> uint16_t gdtr;
Even in 16-bit mode this is a 32-bit base address. And you're
omitting the limit here an below (which is a required part namely
when you expect the hypervisor to access this table).
> };
>
> struct cpu_x86_32 {
> /* Control registers. */
> uint32_t cr[8];
> /* Debug registers. */
> uint32_t dr[8];
> /* GDT descriptor address. */
> uint32_t gdtr;
> };
>
> struct cpu_x86_64 {
> /* Additional amd64 general purpose registers. */
> uint64_t r8, r9, r10, r11, r12, r13, r14, r15;
> /* Control registers. */
> uint64_t cr[9];
[16]
> /* Debug registers. */
> uint64_t dr[8];
> /* Extended Feature Enable Register. */
> uint64_t efer;
> /* GDT descriptor address. */
> uint64_t gdtr;
> };
>
> struct cpu_hvm_regs {
> /* General purpose registers. */
> __DECL_GP_REG(ax);
> __DECL_GP_REG(bx);
> __DECL_GP_REG(cx);
> __DECL_GP_REG(dx);
>
> /* Index registers. */
> __DECL_GP_REG(di);
> __DECL_GP_REG(si);
>
> /* Pointer registers. */
> __DECL_GP_REG(bp);
> __DECL_GP_REG(sp);
Now didn't you agree to use the _natural_ order (i.e. according to
the numbers used to encode registers e.g. in instructions)?
> struct vcpu_hvm_context {
> /* 16bit fields of the strucutre will be used. */
> #define _VCPUHVM_MODE_16B 0
> #define VCPUHVM_MODE_16B (1<<_VCPUHVM_MODE_16B)
> /* 32bit fields of the structure will be used. */
> #define _VCPUHVM_MODE_32B 1
> #define VCPUHVM_MODE_32B (1<<_VCPUHVM_MODE_32B)
> /* 64bit fields of the structure will be used. */
> #define _VCPUHVM_MODE_64B 2
> #define VCPUHVM_MODE_64B (1<<_VCPUHVM_MODE_64B)
As soon as we have three values here, a boolean flag approach
doesn't make sense anymore.
Jan
next prev parent reply other threads:[~2015-07-24 15:49 UTC|newest]
Thread overview: 121+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-03 11:34 [PATCH v3 00/32] Introduce HVM without dm and new boot ABI Roger Pau Monne
2015-07-03 11:34 ` [PATCH v3 01/32] libxc: split x86 HVM setup_guest into smaller logical functions Roger Pau Monne
2015-07-06 10:45 ` Andrew Cooper
2015-07-28 11:22 ` Wei Liu
2015-07-03 11:34 ` [PATCH v3 02/32] libxc: unify xc_dom_p2m_{host/guest} Roger Pau Monne
2015-07-06 10:49 ` Andrew Cooper
2015-07-28 11:22 ` Wei Liu
2015-07-03 11:34 ` [PATCH v3 03/32] libxc: introduce the notion of a container type Roger Pau Monne
2015-07-06 12:01 ` Andrew Cooper
2015-07-28 11:22 ` Wei Liu
2015-07-03 11:34 ` [PATCH v3 04/32] libxc: introduce a domain loader for HVM guest firmware Roger Pau Monne
2015-07-06 12:11 ` Andrew Cooper
2015-07-28 11:22 ` Wei Liu
2015-07-03 11:34 ` [PATCH v3 05/32] libxc: make arch_setup_meminit a xc_dom_arch hook Roger Pau Monne
2015-07-06 12:23 ` Andrew Cooper
2015-07-27 10:40 ` Roger Pau Monné
2015-07-28 11:22 ` Wei Liu
2015-07-03 11:34 ` [PATCH v3 06/32] libxc: make arch_setup_boot{init/late} xc_dom_arch hooks Roger Pau Monne
2015-07-06 12:27 ` Andrew Cooper
2015-07-28 11:22 ` Wei Liu
2015-07-03 11:34 ` [PATCH v3 07/32] xen/x86: fix arch_set_info_guest for HVM guests Roger Pau Monne
2015-07-06 12:58 ` Andrew Cooper
2015-07-23 10:14 ` Roger Pau Monné
2015-07-10 18:39 ` Konrad Rzeszutek Wilk
2015-07-10 18:47 ` Konrad Rzeszutek Wilk
2015-07-23 10:17 ` Roger Pau Monné
2015-07-13 14:01 ` Jan Beulich
2015-07-23 10:25 ` Roger Pau Monné
2015-07-23 11:29 ` Jan Beulich
2015-07-23 11:41 ` Ian Campbell
2015-07-23 15:10 ` Roger Pau Monné
2015-07-23 15:32 ` Jan Beulich
2015-07-23 15:48 ` Roger Pau Monné
2015-07-23 15:58 ` Jan Beulich
2015-07-23 16:00 ` Ian Campbell
2015-07-23 16:15 ` Andrew Cooper
2015-07-23 16:19 ` Jan Beulich
2015-07-23 16:49 ` Andrew Cooper
2015-07-23 17:06 ` Roger Pau Monné
2015-07-23 16:56 ` Roger Pau Monné
2015-07-23 17:12 ` Andrew Cooper
2015-07-24 8:22 ` Jan Beulich
2015-07-24 9:59 ` Roger Pau Monné
2015-07-24 10:46 ` Jan Beulich
2015-07-24 12:11 ` Roger Pau Monné
2015-07-24 12:44 ` Jan Beulich
2015-07-24 15:26 ` Roger Pau Monné
2015-07-24 15:49 ` Jan Beulich [this message]
2015-07-24 16:54 ` Roger Pau Monné
2015-07-24 17:36 ` Konrad Rzeszutek Wilk
2015-07-27 11:55 ` Roger Pau Monné
2015-08-03 16:55 ` Andrew Cooper
2015-08-03 17:31 ` Roger Pau Monné
2015-08-04 18:08 ` Andrew Cooper
2015-08-05 9:53 ` Roger Pau Monné
2015-08-05 15:39 ` Andrew Cooper
2015-08-05 16:40 ` Roger Pau Monné
2015-08-05 16:46 ` Andrew Cooper
2015-08-05 17:11 ` Roger Pau Monné
2015-08-05 19:00 ` Andrew Cooper
2015-08-07 12:15 ` Tim Deegan
2015-08-11 7:26 ` Jan Beulich
2015-07-24 11:11 ` Andrew Cooper
2015-07-24 11:28 ` Ian Campbell
2015-07-24 11:49 ` Jan Beulich
2015-07-24 11:46 ` Jan Beulich
2015-07-24 11:49 ` Roger Pau Monné
2015-07-24 12:41 ` Jan Beulich
2015-07-24 15:28 ` Roger Pau Monné
2015-07-03 11:34 ` [PATCH v3 08/32] libxc: introduce a xc_dom_arch for hvm-3.0-x86_32 guests Roger Pau Monne
2015-07-06 13:40 ` Andrew Cooper
2015-07-03 11:34 ` [PATCH v3 09/32] libxl: switch HVM domain building to use xc_dom_* helpers Roger Pau Monne
2015-07-28 11:22 ` Wei Liu
2015-07-28 14:26 ` Roger Pau Monné
2015-07-28 14:29 ` Wei Liu
2015-07-03 11:34 ` [PATCH v3 10/32] libxc: remove dead HVM building code Roger Pau Monne
2015-07-06 13:46 ` Andrew Cooper
2015-07-23 10:27 ` Roger Pau Monné
2015-07-03 11:34 ` [PATCH v3 11/32] xen/x86: add bitmap of enabled emulated devices Roger Pau Monne
2015-07-06 14:10 ` Andrew Cooper
2015-07-07 7:26 ` Jan Beulich
2015-07-23 10:29 ` Roger Pau Monné
2015-07-03 11:34 ` [PATCH v3 12/32] xen/x86: allow disabling the emulated local apic Roger Pau Monne
2015-07-03 11:34 ` [PATCH v3 13/32] xen/x86: allow disabling the emulated HPET Roger Pau Monne
2015-07-03 11:34 ` [PATCH v3 14/32] xen/x86: allow disabling the pmtimer Roger Pau Monne
2015-07-03 11:34 ` [PATCH v3 15/32] xen/x86: allow disabling the emulated RTC Roger Pau Monne
2015-07-03 11:34 ` [PATCH v3 16/32] xen/x86: allow disabling the emulated IO APIC Roger Pau Monne
2015-07-03 11:34 ` [PATCH v3 17/32] xen/x86: allow disabling the emulated PIC Roger Pau Monne
2015-07-03 11:34 ` [PATCH v3 18/32] xen/x86: allow disabling the emulated pmu Roger Pau Monne
2015-07-03 11:34 ` [PATCH v3 19/32] xen/x86: allow disabling the emulated VGA Roger Pau Monne
2015-07-03 11:34 ` [PATCH v3 20/32] xen/x86: allow disabling the emulated IOMMU Roger Pau Monne
2015-07-03 11:34 ` [PATCH v3 21/32] xen/x86: allow disabling all emulated devices inside of Xen Roger Pau Monne
2015-07-03 11:35 ` [PATCH v3 22/32] elfnotes: intorduce a new PHYS_ENTRY elfnote Roger Pau Monne
2015-07-03 11:35 ` [PATCH v3 23/32] libxc: allow creating domains without emulated devices Roger Pau Monne
2015-07-28 11:22 ` Wei Liu
2015-07-03 11:35 ` [PATCH v3 24/32] xen: allow HVM guests to use XENMEM_memory_map Roger Pau Monne
2015-07-03 11:35 ` [PATCH v3 25/32] xen/x86: allow HVM guests to use hypercalls to bring up vCPUs Roger Pau Monne
2015-07-03 11:35 ` [PATCH v3 26/32] xenconsole: try to attach to PV console if HVM fails Roger Pau Monne
2015-07-14 13:46 ` Stefano Stabellini
2015-07-23 10:30 ` Roger Pau Monné
2015-07-03 11:35 ` [PATCH v3 27/32] libxc: change the position of the special pages Roger Pau Monne
2015-07-03 15:36 ` Roger Pau Monné
2015-07-10 19:06 ` Konrad Rzeszutek Wilk
2015-07-23 10:42 ` Roger Pau Monné
2015-07-03 11:35 ` [PATCH v3 28/32] libxc/xen: introduce HVM_PARAM_CMDLINE_PFN Roger Pau Monne
2015-07-03 11:35 ` [PATCH v3 29/32] libxc/xen: introduce HVM_PARAM_FIRST_FREE_PFN Roger Pau Monne
2015-07-10 19:05 ` Konrad Rzeszutek Wilk
2015-07-23 10:46 ` Roger Pau Monné
2015-07-03 11:35 ` [PATCH v3 30/32] libxc/xen: introduce HVM_PARAM_MODLIST_PFN Roger Pau Monne
2015-07-03 11:35 ` [PATCH v3 31/32] libxc: switch xc_dom_elfloader to be used with HVMlite domains Roger Pau Monne
2015-07-10 19:07 ` Konrad Rzeszutek Wilk
2015-07-23 10:48 ` Roger Pau Monné
2015-07-03 11:35 ` [PATCH v3 32/32] libxl: allow the creation of HVM domains without a device model Roger Pau Monne
2015-07-28 11:22 ` Wei Liu
2015-07-29 14:43 ` Roger Pau Monné
2015-07-29 14:50 ` Wei Liu
2015-07-29 14:58 ` Andrew Cooper
2015-07-03 16:19 ` [PATCH v3 00/32] Introduce HVM without dm and new boot ABI David Vrabel
2015-07-03 16:36 ` Roger Pau Monné
2015-07-10 17:44 ` Konrad Rzeszutek Wilk
2015-07-10 18:01 ` Konrad Rzeszutek Wilk
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