search for: v8086

...code, I noticed that kprobes code was very bogus with respect to segment handling. Many, many bugs are fixed here. I chose to combine the three separate functions that try to do linear address conversion into one, nice and working functions. All of the versions had bugs. 1) Taking an int3 from v8086 mode could cause the kprobes code to read a non-existent LDT. 2) The CS value was not truncated to 16 bit, which could cause an access beyond the bounds of the LDT. 3) The LDT was being read without taking the mm->context semaphore, which means bogus and or non-existent vmalloc()ed pa...

...code, I noticed that kprobes code was very bogus with respect to segment handling. Many, many bugs are fixed here. I chose to combine the three separate functions that try to do linear address conversion into one, nice and working functions. All of the versions had bugs. 1) Taking an int3 from v8086 mode could cause the kprobes code to read a non-existent LDT. 2) The CS value was not truncated to 16 bit, which could cause an access beyond the bounds of the LDT. 3) The LDT was being read without taking the mm->context semaphore, which means bogus and or non-existent vmalloc()ed pa...

> > E_ Under FreeDOS, SYSLINUX.COM doesn't seem to install ldlinux.* > > (specially when used with "--directory"), and there are no ([error]) > > messages; not even when executed with no parameters, or with > > "--help", or with "--version". The messages disappeared _after_ > > 5.00-pre7. > > Right, as Peter pointed out on

.../arch/i386/kernel/entry.S @@ -229,8 +229,9 @@ ret_from_intr: check_userspace: movl EFLAGS(%esp), %eax # mix EFLAGS and CS movb CS(%esp), %al - testl $(VM_MASK | 3), %eax - jz resume_kernel + andl $(VM_MASK | SEGMENT_RPL_MASK), %eax + cmpl $USER_RPL, %eax + jb resume_kernel # not returning to v8086 or userspace ENTRY(resume_userspace) cli # make sure we don't miss an interrupt # setting need_resched or sigpending @@ -367,8 +368,8 @@ restore_all: # See comments in process.c:copy_thread() for details. movb OLDSS(%esp), %ah movb CS(%esp), %al - andl $(VM_MASK | (4 <<...

.../arch/i386/kernel/entry.S @@ -229,8 +229,9 @@ ret_from_intr: check_userspace: movl EFLAGS(%esp), %eax # mix EFLAGS and CS movb CS(%esp), %al - testl $(VM_MASK | 3), %eax - jz resume_kernel + andl $(VM_MASK | SEGMENT_RPL_MASK), %eax + cmpl $USER_RPL, %eax + jb resume_kernel # not returning to v8086 or userspace ENTRY(resume_userspace) cli # make sure we don't miss an interrupt # setting need_resched or sigpending @@ -367,8 +368,8 @@ restore_all: # See comments in process.c:copy_thread() for details. movb OLDSS(%esp), %ah movb CS(%esp), %al - andl $(VM_MASK | (4 <<...

...b/arch/i386/kernel/entry.S Mon Aug 07 14:32:11 2006 +1000 @@ -237,7 +237,7 @@ check_userspace: movl EFLAGS(%esp), %eax # mix EFLAGS and CS movb CS(%esp), %al andl $(VM_MASK | SEGMENT_RPL_MASK), %eax - cmpl $SEGMENT_RPL_MASK, %eax + cmpl $USER_RPL, %eax jb resume_kernel # not returning to v8086 or userspace ENTRY(resume_userspace) DISABLE_INTERRUPTS # make sure we don't miss an interrupt @@ -374,8 +374,8 @@ restore_all: # See comments in process.c:copy_thread() for details. movb OLDSS(%esp), %ah movb CS(%esp), %al - andl $(VM_MASK | (4 << 8) | 3), %eax - cmpl $((4 &lt...

...b/arch/i386/kernel/entry.S Mon Aug 07 14:32:11 2006 +1000 @@ -237,7 +237,7 @@ check_userspace: movl EFLAGS(%esp), %eax # mix EFLAGS and CS movb CS(%esp), %al andl $(VM_MASK | SEGMENT_RPL_MASK), %eax - cmpl $SEGMENT_RPL_MASK, %eax + cmpl $USER_RPL, %eax jb resume_kernel # not returning to v8086 or userspace ENTRY(resume_userspace) DISABLE_INTERRUPTS # make sure we don't miss an interrupt @@ -374,8 +374,8 @@ restore_all: # See comments in process.c:copy_thread() for details. movb OLDSS(%esp), %ah movb CS(%esp), %al - andl $(VM_MASK | (4 << 8) | 3), %eax - cmpl $((4 &lt...

...granted port access, it can not affect the interrupt flag. + + 8) The EIPs at which faults may occur in VMI calls may not match the + original native instruction EIP; this is a bug in the system + today, as many guests do rely on lazy fault handling. + + 9) On entry to V8086 mode, MSR_SYSENTER_CS is cleared to zero. + + 10) Todo - we would like to support these features, but they are not + fully tested and / or implemented: + + Userspace 16-bit stack support + Proper handling of faulting IRETs + +4) ROM Implementation + + Modularization + +...

...granted port access, it can not affect the interrupt flag. + + 8) The EIPs at which faults may occur in VMI calls may not match the + original native instruction EIP; this is a bug in the system + today, as many guests do rely on lazy fault handling. + + 9) On entry to V8086 mode, MSR_SYSENTER_CS is cleared to zero. + + 10) Todo - we would like to support these features, but they are not + fully tested and / or implemented: + + Userspace 16-bit stack support + Proper handling of faulting IRETs + +4) ROM Implementation + + Modularization + +...

Hi Andrew, This series of patches lays the basic ground work for the paravirtualized kernel patches coming later on. I think this lot is ready for the rough-and-tumble world of the -mm tree. The main change from the last posting is that all the page-table related patches have been moved out, and will be posted separately. Also, the off-by-one in reserving the top of address space has been

Hi Andrew, This series of patches lays the basic ground work for the paravirtualized kernel patches coming later on. I think this lot is ready for the rough-and-tumble world of the -mm tree. The main change from the last posting is that all the page-table related patches have been moved out, and will be posted separately. Also, the off-by-one in reserving the top of address space has been

[ REPOST: Apologies to anyone who has seen this before. It didn't make it onto any of the lists it should have. -J ] Hi Andrew, This series of patches lays the basic ground work for the paravirtualized kernel patches coming later on. I think this lot is ready for the rough-and-tumble world of the -mm tree. For the most part, these patches do nothing or very little. The patches should

[ REPOST: Apologies to anyone who has seen this before. It didn't make it onto any of the lists it should have. -J ] Hi Andrew, This series of patches lays the basic ground work for the paravirtualized kernel patches coming later on. I think this lot is ready for the rough-and-tumble world of the -mm tree. For the most part, these patches do nothing or very little. The patches should

OK, this is the revised paravirt.h (Andi has seen this before), then the second is the binary patching stuff. More things get added to the paravirt struct in future patches, but this basic stuff hasn't changed for some time. ==== This patch does the dumbest possible replacement of paravirtualized instructions: calls through a "paravirt_ops" structure. Currently these are function

The following patches introduce the core infrastructure needed to paravirtualize the 32-bit x86 Linux kernel. This is done by moving virtualization sensitive insn's or code paths to a function table, paravirt_ops. This structure can be populated with hypervisor specific calls or native stubs and currently support running on bare metal, VMI, Xen, or Lhype. These patches apply to

The following patches introduce the core infrastructure needed to paravirtualize the 32-bit x86 Linux kernel. This is done by moving virtualization sensitive insn's or code paths to a function table, paravirt_ops. This structure can be populated with hypervisor specific calls or native stubs and currently support running on bare metal, VMI, Xen, or Lhype. These patches apply to