From: Jan Beulich Date: Thu, 17 Apr 2025 08:01:19 +0000 (+0200) Subject: x86/HVM: update repeat count upon nested lin->phys failure X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=c07b16fd6e47782ebf1ee767cd07c1e2b4140f47;p=xen.git x86/HVM: update repeat count upon nested lin->phys failure For the X86EMUL_EXCEPTION case the repeat count must be correctly propagated back. Since for the recursive invocation we use a local helper variable, its value needs copying to the caller's one. While there also correct the off-by-1 range in the comment ahead of the function (strictly speaking for the "DF set" case we'd need to put another, different range there as well). Fixes: 53f87c03b4ea ("x86emul: generalize exception handling for rep_* hooks") Reported-by: Manuel Andreas Signed-off-by: Jan Beulich Reviewed-by: Andrew Cooper --- diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c index 9fff1b82f7..79c180b408 100644 --- a/xen/arch/x86/hvm/emulate.c +++ b/xen/arch/x86/hvm/emulate.c @@ -825,7 +825,7 @@ static void hvmemul_unmap_linear_addr( /* * Convert addr from linear to physical form, valid over the range - * [addr, addr + *reps * bytes_per_rep]. *reps is adjusted according to + * [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. */ @@ -865,7 +865,10 @@ static int hvmemul_linear_to_phys( int rc = hvmemul_linear_to_phys( addr, &_paddr, bytes_per_rep, &one_rep, pfec, hvmemul_ctxt); if ( rc != X86EMUL_OKAY ) + { + *reps = one_rep; return rc; + } pfn = _paddr >> PAGE_SHIFT; } else if ( (pfn = paging_gva_to_gfn(curr, addr, &pfec)) == gfn_x(INVALID_GFN) )