From: Sergiy Kibrik Date: Thu, 1 Aug 2024 11:54:23 +0000 (+0200) Subject: x86/monitor: guard altp2m usage X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=55c01d28f47d5e57bed746ba4e226c7ecbaa2bd1;p=people%2Froyger%2Fxen.git x86/monitor: guard altp2m usage Explicitly check whether altp2m is on for domain when getting altp2m index. If explicit call to altp2m_active() always returns false, DCE will remove call to altp2m_vcpu_idx(). p2m_get_mem_access() expects 0 as altp2m_idx parameter when altp2m not active or not supported, so 0 is a fallback value then. The purpose of that is later to be able to disable altp2m support and exclude its code from the build completely, when not supported by target platform (as of now it's supported for VT-x only). Also all other calls to altp2m_vcpu_idx() are guarded by altp2m_active(), so this change puts usage of this routine in line with the rest of code. Signed-off-by: Sergiy Kibrik Acked-by: Tamas K Lengyel --- diff --git a/xen/arch/x86/hvm/monitor.c b/xen/arch/x86/hvm/monitor.c index 2a8ff07ec9..74621000b2 100644 --- a/xen/arch/x86/hvm/monitor.c +++ b/xen/arch/x86/hvm/monitor.c @@ -262,6 +262,8 @@ bool hvm_monitor_check_p2m(unsigned long gla, gfn_t gfn, uint32_t pfec, struct vcpu *curr = current; vm_event_request_t req = {}; paddr_t gpa = (gfn_to_gaddr(gfn) | (gla & ~PAGE_MASK)); + unsigned int altp2m_idx = altp2m_active(curr->domain) ? + altp2m_vcpu_idx(curr) : 0; int rc; ASSERT(curr->arch.vm_event->send_event); @@ -270,7 +272,7 @@ bool hvm_monitor_check_p2m(unsigned long gla, gfn_t gfn, uint32_t pfec, * p2m_get_mem_access() can fail from a invalid MFN and return -ESRCH * in which case access must be restricted. */ - rc = p2m_get_mem_access(curr->domain, gfn, &access, altp2m_vcpu_idx(curr)); + rc = p2m_get_mem_access(curr->domain, gfn, &access, altp2m_idx); if ( rc == -ESRCH ) access = XENMEM_access_n;