| From 7212bc6c8e9b4a3118e1cc90157c2f123198139e Mon Sep 17 00:00:00 2001 |
| From: Gerd Hoffmann <kraxel@redhat.com> |
| Date: Thu, 16 Jan 2014 10:25:57 +0100 |
| Subject: [PATCH 02/14] pc_piix: document gigabyte_align |
| |
| RH-Author: Gerd Hoffmann <kraxel@redhat.com> |
| Message-id: <1389867959-12463-3-git-send-email-kraxel@redhat.com> |
| Patchwork-id: 56745 |
| O-Subject: [RHEL-7 qemu-kvm PATCH 2/4] pc_piix: document gigabyte_align |
| Bugzilla: 1026548 |
| RH-Acked-by: Laszlo Ersek <lersek@redhat.com> |
| RH-Acked-by: Igor Mammedov <imammedo@redhat.com> |
| RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com> |
| |
| From: "Michael S. Tsirkin" <mst@redhat.com> |
| |
| Document the logic behind the below/above 4G split. |
| |
| Signed-off-by: Michael S. Tsirkin <mst@redhat.com> |
| (cherry picked from commit ecdbfceb0f20a3ef784bf522ed7264660aa3d150) |
| |
| Conflicts: |
| hw/i386/pc_piix.c |
| |
| hw/i386/pc_piix.c | 11 +++++++++++ |
| 1 file changed, 11 insertions(+) |
| |
| Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com> |
| |
| hw/i386/pc_piix.c | 11 +++++++++++ |
| 1 files changed, 11 insertions(+), 0 deletions(-) |
| |
| diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c |
| index 9f1d0b5..12351f9 100644 |
| |
| |
| @@ -61,6 +61,10 @@ static const int ide_irq[MAX_IDE_BUS] = { 14, 15 }; |
| static bool smbios_type1_defaults = true; |
| static bool has_pci_info; |
| static bool has_acpi_build = true; |
| +/* Make sure that guest addresses aligned at 1Gbyte boundaries get mapped to |
| + * host addresses aligned at 1Gbyte boundaries. This way we can use 1GByte |
| + * pages in the host. |
| + */ |
| static bool gigabyte_align = true; |
| |
| /* PC hardware initialisation */ |
| @@ -102,6 +106,13 @@ static void pc_init1(QEMUMachineInitArgs *args, |
| kvmclock_create(); |
| } |
| |
| + /* Check whether RAM fits below 4G (leaving 1/2 GByte for IO memory). |
| + * If it doesn't, we need to split it in chunks below and above 4G. |
| + * In any case, try to make sure that guest addresses aligned at |
| + * 1G boundaries get mapped to host addresses aligned at 1G boundaries. |
| + * For old machine types, use whatever split we used historically to avoid |
| + * breaking migration. |
| + */ |
| if (args->ram_size >= 0xe0000000) { |
| ram_addr_t lowmem = gigabyte_align ? 0xc0000000 : 0xe0000000; |
| above_4g_mem_size = args->ram_size - lowmem; |
| -- |
| 1.7.1 |
| |