Re: [Xen-devel] [PATCH 2/2] x86emul: adjust MOVSXD source operand handling

2019-10-04 Thread Andrew Cooper
On 02/10/2019 10:17, Jan Beulich wrote: > On 02.10.2019 10:51, Andrew Cooper wrote: >> On 02/10/2019 08:07, Jan Beulich wrote: >>> On 01.10.2019 21:44, Andrew Cooper wrote: In this example, hardware can the emulator can disagree by using a different access width. I've been exper

Re: [Xen-devel] [PATCH 2/2] x86emul: adjust MOVSXD source operand handling

2019-10-02 Thread Jan Beulich
On 02.10.2019 10:51, Andrew Cooper wrote: > On 02/10/2019 08:07, Jan Beulich wrote: >> On 01.10.2019 21:44, Andrew Cooper wrote: >>> In this example, hardware can the emulator can disagree by using a >>> different access width. >>> >>> I've been experimenting with my Rome system, and an emulator ha

Re: [Xen-devel] [PATCH 2/2] x86emul: adjust MOVSXD source operand handling

2019-10-02 Thread Andrew Cooper
On 02/10/2019 08:07, Jan Beulich wrote: > On 01.10.2019 21:44, Andrew Cooper wrote: >> In this example, hardware can the emulator can disagree by using a >> different access width. >> >> I've been experimenting with my Rome system, and an emulator hardcoded >> to use 2-byte accesses.  After some in

Re: [Xen-devel] [PATCH 2/2] x86emul: adjust MOVSXD source operand handling

2019-10-02 Thread Jan Beulich
On 01.10.2019 21:44, Andrew Cooper wrote: > In this example, hardware can the emulator can disagree by using a > different access width. > > I've been experimenting with my Rome system, and an emulator hardcoded > to use 2-byte accesses.  After some investigation, the livelock only > occurs for ac

Re: [Xen-devel] [PATCH 2/2] x86emul: adjust MOVSXD source operand handling

2019-10-01 Thread Andrew Cooper
On 19/09/2019 10:31, Jan Beulich wrote: > On 18.09.2019 21:22, Andrew Cooper wrote: >> On 18/09/2019 07:34, Jan Beulich wrote: >>> On 17.09.2019 19:17, Andrew Cooper wrote: On 16/09/2019 10:48, Jan Beulich wrote: > XED commit 1b2fd94425 ("Update MOVSXD to modern behavior") points out >

Re: [Xen-devel] [PATCH 2/2] x86emul: adjust MOVSXD source operand handling

2019-09-19 Thread Jan Beulich
On 18.09.2019 21:22, Andrew Cooper wrote: > On 18/09/2019 07:34, Jan Beulich wrote: >> On 17.09.2019 19:17, Andrew Cooper wrote: >>> On 16/09/2019 10:48, Jan Beulich wrote: XED commit 1b2fd94425 ("Update MOVSXD to modern behavior") points out that as of SDM rev 064 MOVSXD is specified to

Re: [Xen-devel] [PATCH 2/2] x86emul: adjust MOVSXD source operand handling

2019-09-18 Thread Andrew Cooper
On 18/09/2019 07:34, Jan Beulich wrote: > On 17.09.2019 19:17, Andrew Cooper wrote: >> On 16/09/2019 10:48, Jan Beulich wrote: >>> XED commit 1b2fd94425 ("Update MOVSXD to modern behavior") points out >>> that as of SDM rev 064 MOVSXD is specified to read only 16 bits from >>> memory (or register)

Re: [Xen-devel] [PATCH 2/2] x86emul: adjust MOVSXD source operand handling

2019-09-17 Thread Jan Beulich
On 17.09.2019 19:17, Andrew Cooper wrote: > On 16/09/2019 10:48, Jan Beulich wrote: >> XED commit 1b2fd94425 ("Update MOVSXD to modern behavior") points out >> that as of SDM rev 064 MOVSXD is specified to read only 16 bits from >> memory (or register) when used without REX.W and with operand size

Re: [Xen-devel] [PATCH 2/2] x86emul: adjust MOVSXD source operand handling

2019-09-17 Thread Andrew Cooper
On 16/09/2019 10:48, Jan Beulich wrote: > XED commit 1b2fd94425 ("Update MOVSXD to modern behavior") points out > that as of SDM rev 064 MOVSXD is specified to read only 16 bits from > memory (or register) when used without REX.W and with operand size > override. Since the upper 16 bits of the valu

[Xen-devel] [PATCH 2/2] x86emul: adjust MOVSXD source operand handling

2019-09-16 Thread Jan Beulich
XED commit 1b2fd94425 ("Update MOVSXD to modern behavior") points out that as of SDM rev 064 MOVSXD is specified to read only 16 bits from memory (or register) when used without REX.W and with operand size override. Since the upper 16 bits of the value read won't be used anyway in this case, make t