On 08/22/2009 09:37 AM, Borislav Petkov wrote: > On Fri, Aug 21, 2009 at 10:40:18AM -0700, H. Peter Anvin wrote: >> If we're going to modify the paravirt_crap for yet another MSR >> operation, then let's at least make it something like "write_msr_edi" >> and have it take a parameter for the EDI value. Perhaps we should let >> it set EBX and ESI as well (and the same for the read operation, even >> though it already exists.) > > Ok, how about making all rdmsr* variants indirectly call into a > native_read_msr_safe_reg() helper which takes esi and edi as additional > arguments. There was no room for ebx since paravirt has a PVOP_CALL4 > macro which takes the largest number of args - 4 and I am lazy, of > course, to implement a PVOP_CALL5 thing :o) > > The wrmsr variants could be done similarly. > > Suggestions, comments? > Looks reasonable... although part of me wonders if having a pointer to an array containing the entire register file in and out is even better, of if I'm just overengineering at this point. Note that the only difference between "rdmsr" and "wrmsr" is the actual opcode being executed at this point... /* * int native_rdmsr_safe_regs(u32 gprs[8]); * * 32-bit implementation * */ ENTRY(native_rdmsr_safe_regs) push %ebx push %ebp push %esi push %edi push $0 /* Return value */ push %eax movl 4(%eax), %ecx movl 8(%eax), %edx movl 12(%eax), %ebx movl 20(%eax), %ebp movl 24(%eax), %esi movl 28(%eax), %edi movl (%eax), %eax 1: rdmsr 2: push %eax movl 4(%esp), %eax pop (%eax) addl $4, %esp movl %ecx, 4(%eax) movl %edx, 8(%eax) movl %ebx, 12(%eax) movl %ebp, 20(%eax) movl %esi, 24(%eax) movl %edi, 28(%eax) pop %eax pop %edi pop %esi pop %ebp pop %ebx ret 3: movl $-EIO, 4(%esp) jmp 2b __ASM_EX_SEC .balign 4 .long 1b, 3b .previous EXIT(native_rdmsr_safe_regs) /* * int native_rdmsr_safe_regs(u32 gprs[8]); * * 64-bit implementation * */ ENTRY(native_rdmsr_safe_regs) push %rbx push %rbp push $0 /* Return value */ push %rdi movl (%rdi), %eax movl 4(%rdi), %ecx movl 8(%rdi), %edx movl 12(%rdi), %ebx movl 20(%rdi), %ebp movl 24(%rdi), %esi movl 28(%rdi), %edi 1: rdmsr 2: movl %edi, %r10 pop %rdi movl %eax, (%rdi) movl %ecx, 4(%rdi) movl %edx, 8(%rdi) movl %ebx, 12(%rdi) movl %ebp, 20(%rdi) movl %esi, 24(%rdi) movl %r10d, 28(%rdi) pop %rax pop %rbp pop %rbx ret 3: movq $-EIO, 8(%esp) jmp 2b __ASM_EX_SEC .balign 4 .long 1b, 3b .previous EXIT(native_rdmsr_safe_regs) -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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