> -----Original Message-----
> From: Alexandru Stefan ISAILA [mailto:[email protected]]
> Sent: 20 May 2019 13:55
> To: [email protected]
> Cc: Paul Durrant <[email protected]>; [email protected]; Andrew Cooper
> <[email protected]>; Wei Liu <[email protected]>; Roger Pau Monne
> <[email protected]>;
> [email protected]; [email protected]; George Dunlap
> <[email protected]>; Alexandru
> Stefan ISAILA <[email protected]>
> Subject: [PATCH v4 1/2] x86/emulate: Move hvmemul_linear_to_phys
>
> Thiis is done so hvmemul_linear_to_phys() can be called from
> hvmemul_send_vm_event().
>
> Signed-off-by: Alexandru Isaila <[email protected]>
> ---
> xen/arch/x86/hvm/emulate.c | 181 ++++++++++++++++++-------------------
> 1 file changed, 90 insertions(+), 91 deletions(-)
>
> diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
> index 8659c89862..254ff6515d 100644
> --- a/xen/arch/x86/hvm/emulate.c
> +++ b/xen/arch/x86/hvm/emulate.c
> @@ -530,6 +530,95 @@ static int hvmemul_do_mmio_addr(paddr_t mmio_gpa,
> return hvmemul_do_io_addr(1, mmio_gpa, reps, size, dir, df, ram_gpa);
> }
>
I know this is code movement, but it would probably good to a do a bit of
tidying...
> +/*
> + * Convert addr from linear to physical form, valid over the range
> + * [addr, addr + *reps * bytes_per_rep]. *reps is adjusted according to
> + * the valid computed range. It is always >0 when X86EMUL_OKAY is returned.
> + * @pfec indicates the access checks to be performed during page-table walks.
> + */
> +static int hvmemul_linear_to_phys(
> + unsigned long addr,
> + paddr_t *paddr,
> + unsigned int bytes_per_rep,
> + unsigned long *reps,
> + uint32_t pfec,
> + struct hvm_emulate_ctxt *hvmemul_ctxt)
This can all be re-flowed since arg-per-line is not really canonical style.
> +{
> + struct vcpu *curr = current;
> + unsigned long pfn, npfn, done, todo, i, offset = addr & ~PAGE_MASK;
> + int reverse;
Looks like this should be bool.
> +
> + /*
> + * Clip repetitions to a sensible maximum. This avoids extensive looping
> in
> + * this function while still amortising the cost of I/O trap-and-emulate.
> + */
> + *reps = min_t(unsigned long, *reps, 4096);
> +
> + /* With no paging it's easy: linear == physical. */
> + if ( !(curr->arch.hvm.guest_cr[0] & X86_CR0_PG) )
> + {
> + *paddr = addr;
> + return X86EMUL_OKAY;
> + }
> +
> + /* Reverse mode if this is a backwards multi-iteration string operation.
> */
> + reverse = (hvmemul_ctxt->ctxt.regs->eflags & X86_EFLAGS_DF) && (*reps >
> 1);
> +
> + if ( reverse && ((PAGE_SIZE - offset) < bytes_per_rep) )
> + {
> + /* Do page-straddling first iteration forwards via recursion. */
> + paddr_t _paddr;
> + unsigned long one_rep = 1;
> + int rc = hvmemul_linear_to_phys(
> + addr, &_paddr, bytes_per_rep, &one_rep, pfec, hvmemul_ctxt);
Blank line here.
> + if ( rc != X86EMUL_OKAY )
> + return rc;
> + pfn = _paddr >> PAGE_SHIFT;
paddr_to_pfn()
> + }
> + else if ( (pfn = paging_gva_to_gfn(curr, addr, &pfec)) ==
> gfn_x(INVALID_GFN) )
> + {
> + if ( pfec & (PFEC_page_paged | PFEC_page_shared) )
> + return X86EMUL_RETRY;
> + *reps = 0;
> + x86_emul_pagefault(pfec, addr, &hvmemul_ctxt->ctxt);
> + return X86EMUL_EXCEPTION;
> + }
> +
> + done = reverse ? bytes_per_rep + offset : PAGE_SIZE - offset;
> + todo = *reps * bytes_per_rep;
> + for ( i = 1; done < todo; i++ )
> + {
> + /* Get the next PFN in the range. */
> + addr += reverse ? -PAGE_SIZE : PAGE_SIZE;
> + npfn = paging_gva_to_gfn(curr, addr, &pfec);
> +
> + /* Is it contiguous with the preceding PFNs? If not then we're done.
> */
> + if ( (npfn == gfn_x(INVALID_GFN)) ||
> + (npfn != (pfn + (reverse ? -i : i))) )
> + {
> + if ( pfec & (PFEC_page_paged | PFEC_page_shared) )
> + return X86EMUL_RETRY;
> + done /= bytes_per_rep;
> + if ( done == 0 )
> + {
> + ASSERT(!reverse);
> + if ( npfn != gfn_x(INVALID_GFN) )
> + return X86EMUL_UNHANDLEABLE;
> + *reps = 0;
> + x86_emul_pagefault(pfec, addr & PAGE_MASK,
> &hvmemul_ctxt->ctxt);
> + return X86EMUL_EXCEPTION;
> + }
> + *reps = done;
> + break;
> + }
> +
> + done += PAGE_SIZE;
> + }
> +
> + *paddr = ((paddr_t)pfn << PAGE_SHIFT) | offset;
pfn_to_paddr() and a blank line before the return.
> + return X86EMUL_OKAY;
> +}
> +
Thanks,
Paul
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