From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46389) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eqMLw-0007Lk-6t for qemu-devel@nongnu.org; Mon, 26 Feb 2018 12:14:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eqMLs-0004fL-3L for qemu-devel@nongnu.org; Mon, 26 Feb 2018 12:14:16 -0500 Received: from mail-sn1nam02on0111.outbound.protection.outlook.com ([104.47.36.111]:45325 helo=NAM02-SN1-obe.outbound.protection.outlook.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eqMLr-0004es-Rf for qemu-devel@nongnu.org; Mon, 26 Feb 2018 12:14:12 -0500 From: "Justin Terry (VM)" Date: Mon, 26 Feb 2018 09:13:34 -0800 Message-Id: <1519665216-1078-7-git-send-email-juterry@microsoft.com> In-Reply-To: <1519665216-1078-1-git-send-email-juterry@microsoft.com> References: <1519665216-1078-1-git-send-email-juterry@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain Subject: [Qemu-devel] [PATCH 6/8] Fix WHPX issue leaking tpr values List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: pbonzini@redhat.com, rth@twiddle.net, ehabkost@redhat.com, "Justin Terry (VM)" Fixes an issue where if the tpr is assigned to the array but not a different value from what is already expected on the vp the code will skip incrementing the reg_count. In this case its possible that we set an invalid memory section of the next call for DeliverabilityNotifications that was not expected. The fix is to use a local variable to store the temporary tpr and only update the array if the local tpr value is different than the vp context. Signed-off-by: Justin Terry (VM) --- target/i386/whpx-all.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/target/i386/whpx-all.c b/target/i386/whpx-all.c index 7e58d5f68c..47a6935288 100644 --- a/target/i386/whpx-all.c +++ b/target/i386/whpx-all.c @@ -687,6 +687,7 @@ static void whpx_vcpu_pre_run(CPUState *cpu) struct CPUX86State *env = (CPUArchState *)(cpu->env_ptr); X86CPU *x86_cpu = X86_CPU(cpu); int irq; + uint8_t tpr; WHV_X64_PENDING_INTERRUPTION_REGISTER new_int = {0}; UINT32 reg_count = 0; WHV_REGISTER_VALUE reg_values[3] = {0}; @@ -746,9 +747,10 @@ static void whpx_vcpu_pre_run(CPUState *cpu) } /* Sync the TPR to the CR8 if was modified during the intercept */ - reg_values[reg_count].Reg64 = cpu_get_apic_tpr(x86_cpu->apic_state); - if (reg_values[reg_count].Reg64 != vcpu->tpr) { - vcpu->tpr = reg_values[reg_count].Reg64; + tpr = cpu_get_apic_tpr(x86_cpu->apic_state); + if (tpr != vcpu->tpr) { + vcpu->tpr = tpr; + reg_values[reg_count].Reg64 = tpr; cpu->exit_request = 1; reg_names[reg_count] = WHvX64RegisterCr8; reg_count += 1; -- 2.13.6