[RFC PATCH v3 0/2] KVM: x86: Allow Qemu/KVM to use PVH entry point
Changes from v2: * All structures (including memory map table entries) are padded and aligned to an 8 byte boundary. * Removed the "packed" attributes and made changes to comments as suggested by Jan. Changes from v1: * Adopted Paolo's suggestion for defining a v2 PVH ABI that includes the e820 map instead of using the second module entry to pass the table. * Cleaned things up a bit to reduce the number of xen vs non-xen special cases. Maran Wilson (2): xen/pvh: Add memory map pointer to hvm_start_info struct KVM: x86: Allow Qemu/KVM to use PVH entry point arch/x86/xen/enlighten_pvh.c | 51 --- include/xen/interface/hvm/start_info.h | 50 +- 2 files changed, 85 insertions(+), 16 deletions(-)
[RFC PATCH v3 1/2] xen/pvh: Add memory map pointer to hvm_start_info struct
The start info structure that is defined as part of the x86/HVM direct
boot ABI and used for starting Xen PVH guests would be more versatile if
it also included a way to pass information about the memory map to the
guest. This would allow KVM guests to share the same entry point.
---
include/xen/interface/hvm/start_info.h | 50 +-
1 file changed, 49 insertions(+), 1 deletion(-)
diff --git a/include/xen/interface/hvm/start_info.h
b/include/xen/interface/hvm/start_info.h
index 6484159..80cfbd3 100644
--- a/include/xen/interface/hvm/start_info.h
+++ b/include/xen/interface/hvm/start_info.h
@@ -33,7 +33,7 @@
*| magic | Contains the magic value XEN_HVM_START_MAGIC_VALUE
*|| ("xEn3" with the 0x80 bit of the "E" set).
* 4 ++
- *| version| Version of this structure. Current version is 0. New
+ *| version| Version of this structure. Current version is 1. New
*|| versions are guaranteed to be backwards-compatible.
* 8 ++
*| flags | SIF_xxx flags.
@@ -48,6 +48,15 @@
* 32 ++
*| rsdp_paddr | Physical address of the RSDP ACPI data structure.
* 40 ++
+ *| memmap_paddr | Physical address of the (optional) memory map. Only
+ *|| present in version 1 and newer of the structure.
+ * 48 ++
+ *| memmap_entries | Number of entries in the memory map table. Only
+ *|| present in version 1 and newer of the structure.
+ *|| Zero if there is no memory map being provided.
+ * 52 ++
+ *| reserved | Version 1 and newer only.
+ * 56 ++
*
* The layout of each entry in the module structure is the following:
*
@@ -62,10 +71,34 @@
*| reserved |
* 32 ++
*
+ * The layout of each entry in the memory map table is as follows:
+ *
+ * 0 ++
+ *| addr | Base address
+ * 8 ++
+ *| size | Size of mapping in bytes
+ * 16 ++
+ *| type | Type of mapping as defined between the hypervisor
+ *|| and guest it's starting. E820_TYPE_xxx, for example.
+ * 20 +|
+ *| reserved |
+ * 24 ++
+ *
* The address and sizes are always a 64bit little endian unsigned integer.
*
* NB: Xen on x86 will always try to place all the data below the 4GiB
* boundary.
+ *
+ * Version numbers of the hvm_start_info structure have evolved like this:
+ *
+ * Version 0:
+ *
+ * Version 1: Added the memmap_paddr/memmap_entries fields (plus 4 bytes of
+ * padding) to the end of the hvm_start_info struct. These new
+ * fields can be used to pass a memory map to the guest. The
+ * memory map is optional and so guests that understand version 1
+ * of the structure must check that memmap_entries is non-zero
+ * before trying to read the memory map.
*/
#define XEN_HVM_START_MAGIC_VALUE 0x336ec578
@@ -86,6 +119,14 @@ struct hvm_start_info {
uint64_t cmdline_paddr; /* Physical address of the command line. */
uint64_t rsdp_paddr;/* Physical address of the RSDP ACPI data*/
/* structure.*/
+uint64_t memmap_paddr; /* Physical address of an array of */
+ /* hvm_memmap_table_entry. Only present in */
+ /* version 1 and newer of the structure */
+uint32_t memmap_entries; /* Number of entries in the memmap table.*/
+ /* Only present in version 1 and newer of*/
+ /* the structure. Value will be zero if */
+ /* there is no memory map being provided.*/
+uint32_t reserved;
};
struct hvm_modlist_entry {
@@ -95,4 +136,11 @@ struct hvm_modlist_entry {
uint64_t reserved;
};
+struct hvm_memmap_table_entry {
+uint64_t addr; /* Base address of the memory region */
+uint64_t size; /* Size of the memory region in bytes*/
+uint32_t type; /* Mapping type */
+uint32_t reserved;
+};
+
#endif /* __XEN_PUBLIC_ARCH_X86_HVM_START_INFO_H__ */
--
1.8.3.1
[RFC PATCH v3 2/2] KVM: x86: Allow Qemu/KVM to use PVH entry point
For certain applications it is desirable to rapidly boot a KVM virtual
machine. In cases where legacy hardware and software support within the
guest is not needed, Qemu should be able to boot directly into the
uncompressed Linux kernel binary without the need to run firmware.
There already exists an ABI to allow this for Xen PVH guests and the ABI
is supported by Linux and FreeBSD:
https://xenbits.xen.org/docs/unstable/misc/pvh.html
This patch enables Qemu to use that same entry point for booting KVM
guests.
---
arch/x86/xen/enlighten_pvh.c | 51 +++-
1 file changed, 36 insertions(+), 15 deletions(-)
diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c
index 98ab176..12f3716 100644
--- a/arch/x86/xen/enlighten_pvh.c
+++ b/arch/x86/xen/enlighten_pvh.c
@@ -31,21 +31,38 @@ static void xen_pvh_arch_setup(void)
acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
}
-static void __init init_pvh_bootparams(void)
+static void __init init_pvh_bootparams(bool xen_guest)
{
struct xen_memory_map memmap;
int rc;
memset(_bootparams, 0, sizeof(pvh_bootparams));
- memmap.nr_entries = ARRAY_SIZE(pvh_bootparams.e820_table);
- set_xen_guest_handle(memmap.buffer, pvh_bootparams.e820_table);
- rc = HYPERVISOR_memory_op(XENMEM_memory_map, );
- if (rc) {
- xen_raw_printk("XENMEM_memory_map failed (%d)\n", rc);
+ if ((pvh_start_info.version > 0) && (pvh_start_info.memmap_entries)) {
+ struct hvm_memmap_table_entry *ep;
+ int i;
+
+ ep = __va(pvh_start_info.memmap_paddr);
+ pvh_bootparams.e820_entries = pvh_start_info.memmap_entries;
+
+ for (i = 0; i < pvh_bootparams.e820_entries ; i++, ep++) {
+ pvh_bootparams.e820_table[i].addr = ep->addr;
+ pvh_bootparams.e820_table[i].size = ep->size;
+ pvh_bootparams.e820_table[i].type = ep->type;
+ }
+ } else if (xen_guest) {
+ memmap.nr_entries = ARRAY_SIZE(pvh_bootparams.e820_table);
+ set_xen_guest_handle(memmap.buffer, pvh_bootparams.e820_table);
+ rc = HYPERVISOR_memory_op(XENMEM_memory_map, );
+ if (rc) {
+ xen_raw_printk("XENMEM_memory_map failed (%d)\n", rc);
+ BUG();
+ }
+ pvh_bootparams.e820_entries = memmap.nr_entries;
+ } else {
+ xen_raw_printk("Error: Could not find memory map\n");
BUG();
}
- pvh_bootparams.e820_entries = memmap.nr_entries;
if (pvh_bootparams.e820_entries < E820_MAX_ENTRIES_ZEROPAGE - 1) {
pvh_bootparams.e820_table[pvh_bootparams.e820_entries].addr =
@@ -76,7 +93,7 @@ static void __init init_pvh_bootparams(void)
* environment (i.e. hardware_subarch 0).
*/
pvh_bootparams.hdr.version = 0x212;
- pvh_bootparams.hdr.type_of_loader = (9 << 4) | 0; /* Xen loader */
+ pvh_bootparams.hdr.type_of_loader = ((xen_guest ? 0x9 : 0xb) << 4) | 0;
}
/*
@@ -85,8 +102,10 @@ static void __init init_pvh_bootparams(void)
*/
void __init xen_prepare_pvh(void)
{
- u32 msr;
+
+ u32 msr = xen_cpuid_base();
u64 pfn;
+ bool xen_guest = !!msr;
if (pvh_start_info.magic != XEN_HVM_START_MAGIC_VALUE) {
xen_raw_printk("Error: Unexpected magic value (0x%08x)\n",
@@ -94,13 +113,15 @@ void __init xen_prepare_pvh(void)
BUG();
}
- xen_pvh = 1;
+ if (xen_guest) {
+ xen_pvh = 1;
- msr = cpuid_ebx(xen_cpuid_base() + 2);
- pfn = __pa(hypercall_page);
- wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
+ msr = cpuid_ebx(msr + 2);
+ pfn = __pa(hypercall_page);
+ wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
- init_pvh_bootparams();
+ x86_init.oem.arch_setup = xen_pvh_arch_setup;
+ }
- x86_init.oem.arch_setup = xen_pvh_arch_setup;
+ init_pvh_bootparams(xen_guest);
}
--
1.8.3.1
Re: [PATCH v7 0/7] KVM: x86: Allow Qemu/KVM to use PVH entry point
On 5/18/2018 4:31 AM, Paolo Bonzini wrote: On 16/05/2018 22:27, Maran Wilson wrote: Friendly ping. I am hopeful one of the x86 and/or KVM maintainers has a few cycles to spare to look this over. And thanks to everyone who has helped thus far by providing valuable feedback and reviewing. https://lkml.org/lkml/2018/4/16/1002 KVM bits look fine. This would be the right time to post the QEMU patches... Thanks Paolo. Yes, we will have the Qemu patches out soon. It is being actively worked. We have had one implementation in place, but decided to re-implement things slightly based on some preliminary feedback before sending it out to the wider community. Thanks, -Maran Paolo
Re: [PATCH v8 0/7] KVM: x86: Allow Qemu/KVM to use PVH entry point
On 12/6/2018 1:21 PM, Paolo Bonzini wrote: On 06/12/18 07:02, Maran Wilson wrote: For certain applications it is desirable to rapidly boot a KVM virtual machine. In cases where legacy hardware and software support within the guest is not needed, Qemu should be able to boot directly into the uncompressed Linux kernel binary without the need to run firmware. There already exists an ABI to allow this for Xen PVH guests and the ABI is supported by Linux and FreeBSD: https://xenbits.xen.org/docs/unstable/misc/pvh.html This patch series would enable Qemu to use that same entry point for booting KVM guests. Thanks! I should be able to post a Tested-by next Monday. Boris, are you going to pick it up for 4.21? Hi Paolo, Are you still planning on running some testing of your own for these patches? Should Boris wait to hear from you before moving forward? Thanks, -Maran Paolo
Re: [PATCH v9 0/7] KVM: x86: Allow Qemu/KVM to use PVH entry point
On 12/12/2018 12:39 PM, Borislav Petkov wrote: On Tue, Dec 11, 2018 at 11:29:21AM -0800, Maran Wilson wrote: Is your question about what options you need to provide to Qemu? Or is your question about the SW implementation choices? Assuming the former... Yeah, that's what I wanted to know. But looking at it, I'm booting bzImage here just as quickly and as flexible so I don't see the advantage of this new method for my use case here of booting kernels in qemu. But maybe there's a good use case where firmware is slow and one doesn't really wanna noodle through it or when one does start a gazillion VMs per second or whatever... Right, the time saved is not something you would notice while starting a VM manually. But it does reduce the time to reach startup_64() in Linux by about 50% (going from around 94ms to around 47ms) when booting a VM using Qemu+qboot (for example). That time savings becomes pretty important when you are trying to use VMs as containers (for instance, as is the case with Kata containers) and trying to get the latency for launching such a container really low -- to come as close as possible to match the latency for launching more traditional containers that don't have the additional security/isolation of running within a separate VM. Thanks, -Maran Thx.
[PATCH v9 0/7] KVM: x86: Allow Qemu/KVM to use PVH entry point
here
is a compelling reason for not using __weak in this situation.
Changes from v2:
* All structures (including memory map table entries) are padded and
aligned to an 8 byte boundary.
* Removed the "packed" attributes and made changes to comments as
suggested by Jan.
Changes from v1:
* Adopted Paolo's suggestion for defining a v2 PVH ABI that includes the
e820 map instead of using the second module entry to pass the table.
* Cleaned things up a bit to reduce the number of xen vs non-xen special
cases.
Maran Wilson (7):
xen/pvh: Split CONFIG_XEN_PVH into CONFIG_PVH and CONFIG_XEN_PVH
xen/pvh: Move PVH entry code out of Xen specific tree
xen/pvh: Create a new file for Xen specific PVH code
xen/pvh: Move Xen specific PVH VM initialization out of common file
xen/pvh: Move Xen code for getting mem map via hcall out of common
file
xen/pvh: Add memory map pointer to hvm_start_info struct
KVM: x86: Allow Qemu/KVM to use PVH entry point
MAINTAINERS | 1 +
arch/x86/Kbuild | 2 +
arch/x86/Kconfig| 6 ++
arch/x86/kernel/head_64.S | 2 +-
arch/x86/platform/pvh/Makefile | 5 +
arch/x86/platform/pvh/enlighten.c | 137
arch/x86/{xen/xen-pvh.S => platform/pvh/head.S} | 0
arch/x86/xen/Kconfig| 3 +-
arch/x86/xen/Makefile | 2 -
arch/x86/xen/enlighten_pvh.c| 94
include/xen/interface/hvm/start_info.h | 63 ++-
include/xen/xen.h | 3 +
12 files changed, 237 insertions(+), 81 deletions(-)
create mode 100644 arch/x86/platform/pvh/Makefile
create mode 100644 arch/x86/platform/pvh/enlighten.c
rename arch/x86/{xen/xen-pvh.S => platform/pvh/head.S} (100%)
--
2.16.1
[PATCH v9 1/7] xen/pvh: Split CONFIG_XEN_PVH into CONFIG_PVH and CONFIG_XEN_PVH
In order to pave the way for hypervisors other than Xen to use the PVH entry point for VMs, we need to factor the PVH entry code into Xen specific and hypervisor agnostic components. The first step in doing that, is to create a new config option for PVH entry that can be enabled independently from CONFIG_XEN. Signed-off-by: Maran Wilson Reviewed-by: Juergen Gross --- arch/x86/Kconfig | 6 ++ arch/x86/kernel/head_64.S | 2 +- arch/x86/xen/Kconfig | 3 ++- 3 files changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 8689e794a43c..c2a22a74abee 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -796,6 +796,12 @@ config KVM_GUEST underlying device model, the host provides the guest with timing infrastructure such as time of day, and system time +config PVH + bool "Support for running PVH guests" + ---help--- + This option enables the PVH entry point for guest virtual machines + as specified in the x86/HVM direct boot ABI. + config KVM_DEBUG_FS bool "Enable debug information for KVM Guests in debugfs" depends on KVM_GUEST && DEBUG_FS diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 747c758f67b7..d1dbe8e4eb82 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -386,7 +386,7 @@ NEXT_PAGE(early_dynamic_pgts) .data -#if defined(CONFIG_XEN_PV) || defined(CONFIG_XEN_PVH) +#if defined(CONFIG_XEN_PV) || defined(CONFIG_PVH) NEXT_PGD_PAGE(init_top_pgt) .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC .orginit_top_pgt + L4_PAGE_OFFSET*8, 0 diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig index 1ef391aa184d..e07abefd3d26 100644 --- a/arch/x86/xen/Kconfig +++ b/arch/x86/xen/Kconfig @@ -74,6 +74,7 @@ config XEN_DEBUG_FS Enabling this option may incur a significant performance overhead. config XEN_PVH - bool "Support for running as a PVH guest" + bool "Support for running as a Xen PVH guest" depends on XEN && XEN_PVHVM && ACPI + select PVH def_bool n -- 2.16.1
[PATCH v9 2/7] xen/pvh: Move PVH entry code out of Xen specific tree
Once hypervisors other than Xen start using the PVH entry point for
starting VMs, we would like the option of being able to compile PVH entry
capable kernels without enabling CONFIG_XEN and all the code that comes
along with that. To allow that, we are moving the PVH code out of Xen and
into files sitting at a higher level in the tree.
This patch is not introducing any code or functional changes, just moving
files from one location to another.
Signed-off-by: Maran Wilson
Reviewed-by: Konrad Rzeszutek Wilk
Reviewed-by: Juergen Gross
---
MAINTAINERS| 1 +
arch/x86/Kbuild| 2 ++
arch/x86/platform/pvh/Makefile | 5 +
arch/x86/{xen/enlighten_pvh.c => platform/pvh/enlighten.c} | 0
arch/x86/{xen/xen-pvh.S => platform/pvh/head.S}| 0
arch/x86/xen/Makefile | 4
6 files changed, 8 insertions(+), 4 deletions(-)
create mode 100644 arch/x86/platform/pvh/Makefile
rename arch/x86/{xen/enlighten_pvh.c => platform/pvh/enlighten.c} (100%)
rename arch/x86/{xen/xen-pvh.S => platform/pvh/head.S} (100%)
diff --git a/MAINTAINERS b/MAINTAINERS
index d27401df091f..477ab97c2062 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16461,6 +16461,7 @@ L: xen-de...@lists.xenproject.org (moderated for
non-subscribers)
T: git git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git
S: Supported
F: arch/x86/xen/
+F: arch/x86/platform/pvh/
F: drivers/*/xen-*front.c
F: drivers/xen/
F: arch/x86/include/asm/xen/
diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild
index 0038a2d10a7a..2089e4414300 100644
--- a/arch/x86/Kbuild
+++ b/arch/x86/Kbuild
@@ -7,6 +7,8 @@ obj-$(CONFIG_KVM) += kvm/
# Xen paravirtualization support
obj-$(CONFIG_XEN) += xen/
+obj-$(CONFIG_XEN_PVH) += platform/pvh/
+
# Hyper-V paravirtualization support
obj-$(subst m,y,$(CONFIG_HYPERV)) += hyperv/
diff --git a/arch/x86/platform/pvh/Makefile b/arch/x86/platform/pvh/Makefile
new file mode 100644
index ..9fd25efcd2a3
--- /dev/null
+++ b/arch/x86/platform/pvh/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+OBJECT_FILES_NON_STANDARD_head.o := y
+
+obj-$(CONFIG_XEN_PVH) += enlighten.o
+obj-$(CONFIG_XEN_PVH) += head.o
diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/platform/pvh/enlighten.c
similarity index 100%
rename from arch/x86/xen/enlighten_pvh.c
rename to arch/x86/platform/pvh/enlighten.c
diff --git a/arch/x86/xen/xen-pvh.S b/arch/x86/platform/pvh/head.S
similarity index 100%
rename from arch/x86/xen/xen-pvh.S
rename to arch/x86/platform/pvh/head.S
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index dd2550d33b38..b239922f6c6c 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -1,6 +1,5 @@
# SPDX-License-Identifier: GPL-2.0
OBJECT_FILES_NON_STANDARD_xen-asm_$(BITS).o := y
-OBJECT_FILES_NON_STANDARD_xen-pvh.o := y
ifdef CONFIG_FUNCTION_TRACER
# Do not profile debug and lowlevel utilities
@@ -37,9 +36,6 @@ obj-$(CONFIG_XEN_PV) += multicalls.o
obj-$(CONFIG_XEN_PV) += xen-asm.o
obj-$(CONFIG_XEN_PV) += xen-asm_$(BITS).o
-obj-$(CONFIG_XEN_PVH) += enlighten_pvh.o
-obj-$(CONFIG_XEN_PVH) += xen-pvh.o
-
obj-$(CONFIG_EVENT_TRACING)+= trace.o
obj-$(CONFIG_SMP) += smp.o
--
2.16.1
[PATCH v9 3/7] xen/pvh: Create a new file for Xen specific PVH code
We need to refactor PVH entry code so that support for other hypervisors
like Qemu/KVM can be added more easily.
The first step in that direction is to create a new file that will
eventually hold the Xen specific routines.
Signed-off-by: Maran Wilson
Reviewed-by: Juergen Gross
---
arch/x86/platform/pvh/enlighten.c | 5 ++---
arch/x86/xen/Makefile | 2 ++
arch/x86/xen/enlighten_pvh.c | 10 ++
3 files changed, 14 insertions(+), 3 deletions(-)
create mode 100644 arch/x86/xen/enlighten_pvh.c
diff --git a/arch/x86/platform/pvh/enlighten.c
b/arch/x86/platform/pvh/enlighten.c
index 02e3ab7ff242..491932991202 100644
--- a/arch/x86/platform/pvh/enlighten.c
+++ b/arch/x86/platform/pvh/enlighten.c
@@ -18,10 +18,9 @@
/*
* PVH variables.
*
- * xen_pvh pvh_bootparams and pvh_start_info need to live in data segment
- * since they are used after startup_{32|64}, which clear .bss, are invoked.
+ * pvh_bootparams and pvh_start_info need to live in the data segment since
+ * they are used after startup_{32|64}, which clear .bss, are invoked.
*/
-bool xen_pvh __attribute__((section(".data"))) = 0;
struct boot_params pvh_bootparams __attribute__((section(".data")));
struct hvm_start_info pvh_start_info __attribute__((section(".data")));
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index b239922f6c6c..084de77a109e 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -36,6 +36,8 @@ obj-$(CONFIG_XEN_PV) += multicalls.o
obj-$(CONFIG_XEN_PV) += xen-asm.o
obj-$(CONFIG_XEN_PV) += xen-asm_$(BITS).o
+obj-$(CONFIG_XEN_PVH) += enlighten_pvh.o
+
obj-$(CONFIG_EVENT_TRACING)+= trace.o
obj-$(CONFIG_SMP) += smp.o
diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c
new file mode 100644
index ..6be7bc719b38
--- /dev/null
+++ b/arch/x86/xen/enlighten_pvh.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+#include
+
+/*
+ * PVH variables.
+ *
+ * The variable xen_pvh needs to live in the data segment since it is used
+ * after startup_{32|64} is invoked, which will clear the .bss segment.
+ */
+bool xen_pvh __attribute__((section(".data"))) = 0;
--
2.16.1
[PATCH v9 4/7] xen/pvh: Move Xen specific PVH VM initialization out of common file
We need to refactor PVH entry code so that support for other hypervisors
like Qemu/KVM can be added more easily.
This patch moves the small block of code used for initializing Xen PVH
virtual machines into the Xen specific file. This initialization is not
going to be needed for Qemu/KVM guests. Moving it out of the common file
is going to allow us to compile kernels in the future without CONFIG_XEN
that are still capable of being booted as a Qemu/KVM guest via the PVH
entry point.
Signed-off-by: Maran Wilson
Reviewed-by: Konrad Rzeszutek Wilk
Reviewed-by: Juergen Gross
---
arch/x86/platform/pvh/enlighten.c | 29 -
arch/x86/xen/enlighten_pvh.c | 22 +-
include/xen/xen.h | 3 +++
3 files changed, 44 insertions(+), 10 deletions(-)
diff --git a/arch/x86/platform/pvh/enlighten.c
b/arch/x86/platform/pvh/enlighten.c
index 491932991202..637bd74ba32d 100644
--- a/arch/x86/platform/pvh/enlighten.c
+++ b/arch/x86/platform/pvh/enlighten.c
@@ -81,27 +81,38 @@ static void __init init_pvh_bootparams(void)
x86_init.acpi.get_root_pointer = pvh_get_root_pointer;
}
+/*
+ * If we are trying to boot a Xen PVH guest, it is expected that the kernel
+ * will have been configured to provide the required override for this routine.
+ */
+void __init __weak xen_pvh_init(void)
+{
+ xen_raw_printk("Error: Missing xen PVH initialization\n");
+ BUG();
+}
+
+/*
+ * When we add support for other hypervisors like Qemu/KVM, this routine can
+ * selectively invoke the appropriate initialization based on guest type.
+ */
+static void hypervisor_specific_init(void)
+{
+ xen_pvh_init();
+}
+
/*
* This routine (and those that it might call) should not use
* anything that lives in .bss since that segment will be cleared later.
*/
void __init xen_prepare_pvh(void)
{
- u32 msr;
- u64 pfn;
-
if (pvh_start_info.magic != XEN_HVM_START_MAGIC_VALUE) {
xen_raw_printk("Error: Unexpected magic value (0x%08x)\n",
pvh_start_info.magic);
BUG();
}
- xen_pvh = 1;
- xen_start_flags = pvh_start_info.flags;
-
- msr = cpuid_ebx(xen_cpuid_base() + 2);
- pfn = __pa(hypercall_page);
- wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
+ hypervisor_specific_init();
init_pvh_bootparams();
}
diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c
index 6be7bc719b38..41a7d6ad74e0 100644
--- a/arch/x86/xen/enlighten_pvh.c
+++ b/arch/x86/xen/enlighten_pvh.c
@@ -1,5 +1,12 @@
// SPDX-License-Identifier: GPL-2.0
-#include
+#include
+
+#include
+#include
+
+#include
+#include
+#include
/*
* PVH variables.
@@ -8,3 +15,16 @@
* after startup_{32|64} is invoked, which will clear the .bss segment.
*/
bool xen_pvh __attribute__((section(".data"))) = 0;
+
+void __init xen_pvh_init(void)
+{
+ u32 msr;
+ u64 pfn;
+
+ xen_pvh = 1;
+ xen_start_flags = pvh_start_info.flags;
+
+ msr = cpuid_ebx(xen_cpuid_base() + 2);
+ pfn = __pa(hypercall_page);
+ wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
+}
diff --git a/include/xen/xen.h b/include/xen/xen.h
index d7a2678da77f..0e2156786ad2 100644
--- a/include/xen/xen.h
+++ b/include/xen/xen.h
@@ -29,6 +29,9 @@ extern bool xen_pvh;
extern uint32_t xen_start_flags;
+#include
+extern struct hvm_start_info pvh_start_info;
+
#ifdef CONFIG_XEN_DOM0
#include
#include
--
2.16.1
[PATCH v9 6/7] xen/pvh: Add memory map pointer to hvm_start_info struct
The start info structure that is defined as part of the x86/HVM direct boot
ABI and used for starting Xen PVH guests would be more versatile if it also
included a way to pass information about the memory map to the guest. This
would allow KVM guests to share the same entry point.
Signed-off-by: Maran Wilson
Reviewed-by: Juergen Gross
---
include/xen/interface/hvm/start_info.h | 63 +-
1 file changed, 62 insertions(+), 1 deletion(-)
diff --git a/include/xen/interface/hvm/start_info.h
b/include/xen/interface/hvm/start_info.h
index 648415976ead..50af9ea2ff1e 100644
--- a/include/xen/interface/hvm/start_info.h
+++ b/include/xen/interface/hvm/start_info.h
@@ -33,7 +33,7 @@
*| magic | Contains the magic value XEN_HVM_START_MAGIC_VALUE
*|| ("xEn3" with the 0x80 bit of the "E" set).
* 4 ++
- *| version| Version of this structure. Current version is 0. New
+ *| version| Version of this structure. Current version is 1. New
*|| versions are guaranteed to be backwards-compatible.
* 8 ++
*| flags | SIF_xxx flags.
@@ -48,6 +48,15 @@
* 32 ++
*| rsdp_paddr | Physical address of the RSDP ACPI data structure.
* 40 ++
+ *| memmap_paddr | Physical address of the (optional) memory map. Only
+ *|| present in version 1 and newer of the structure.
+ * 48 ++
+ *| memmap_entries | Number of entries in the memory map table. Zero
+ *|| if there is no memory map being provided. Only
+ *|| present in version 1 and newer of the structure.
+ * 52 ++
+ *| reserved | Version 1 and newer only.
+ * 56 ++
*
* The layout of each entry in the module structure is the following:
*
@@ -62,13 +71,51 @@
*| reserved |
* 32 ++
*
+ * The layout of each entry in the memory map table is as follows:
+ *
+ * 0 ++
+ *| addr | Base address
+ * 8 ++
+ *| size | Size of mapping in bytes
+ * 16 ++
+ *| type | Type of mapping as defined between the hypervisor
+ *|| and guest. See XEN_HVM_MEMMAP_TYPE_* values below.
+ * 20 +|
+ *| reserved |
+ * 24 ++
+ *
* The address and sizes are always a 64bit little endian unsigned integer.
*
* NB: Xen on x86 will always try to place all the data below the 4GiB
* boundary.
+ *
+ * Version numbers of the hvm_start_info structure have evolved like this:
+ *
+ * Version 0: Initial implementation.
+ *
+ * Version 1: Added the memmap_paddr/memmap_entries fields (plus 4 bytes of
+ * padding) to the end of the hvm_start_info struct. These new
+ * fields can be used to pass a memory map to the guest. The
+ * memory map is optional and so guests that understand version 1
+ * of the structure must check that memmap_entries is non-zero
+ * before trying to read the memory map.
*/
#define XEN_HVM_START_MAGIC_VALUE 0x336ec578
+/*
+ * The values used in the type field of the memory map table entries are
+ * defined below and match the Address Range Types as defined in the "System
+ * Address Map Interfaces" section of the ACPI Specification. Please refer to
+ * section 15 in version 6.2 of the ACPI spec: http://uefi.org/specifications
+ */
+#define XEN_HVM_MEMMAP_TYPE_RAM 1
+#define XEN_HVM_MEMMAP_TYPE_RESERVED 2
+#define XEN_HVM_MEMMAP_TYPE_ACPI 3
+#define XEN_HVM_MEMMAP_TYPE_NVS 4
+#define XEN_HVM_MEMMAP_TYPE_UNUSABLE 5
+#define XEN_HVM_MEMMAP_TYPE_DISABLED 6
+#define XEN_HVM_MEMMAP_TYPE_PMEM 7
+
/*
* C representation of the x86/HVM start info layout.
*
@@ -86,6 +133,13 @@ struct hvm_start_info {
uint64_t cmdline_paddr; /* Physical address of the command line. */
uint64_t rsdp_paddr;/* Physical address of the RSDP ACPI data*/
/* structure.*/
+/* All following fields only present in version 1 and newer */
+uint64_t memmap_paddr; /* Physical address of an array of */
+/* hvm_memmap_table_entry. */
+uint32_t memmap_entries;/* Number of entries in the memmap table.*/
+/* Value will be zero if there is no memory */
+/* map being provided. */
+uint32_t reserved; /* Must be zero. */
};
struct hvm_modlist_entry {
@@ -95,4 +149,11 @@ struct hvm_modlist_entry {
uint64_t reserved;
};
+struct hvm_memmap_table_entry {
+uint64_t addr; /* Bas
[PATCH v9 5/7] xen/pvh: Move Xen code for getting mem map via hcall out of common file
We need to refactor PVH entry code so that support for other hypervisors
like Qemu/KVM can be added more easily.
The original design for PVH entry in Xen guests relies on being able to
obtain the memory map from the hypervisor using a hypercall. When we
extend the PVH entry ABI to support other hypervisors like Qemu/KVM,
a new mechanism will be added that allows the guest to get the memory
map without needing to use hypercalls.
For Xen guests, the hypercall approach will still be supported. In
preparation for adding support for other hypervisors, we can move the
code that uses hypercalls into the Xen specific file. This will allow us
to compile kernels in the future without CONFIG_XEN that are still capable
of being booted as a Qemu/KVM guest via the PVH entry point.
Signed-off-by: Maran Wilson
Reviewed-by: Juergen Gross
---
arch/x86/platform/pvh/enlighten.c | 29 ++---
arch/x86/xen/enlighten_pvh.c | 20
2 files changed, 34 insertions(+), 15 deletions(-)
diff --git a/arch/x86/platform/pvh/enlighten.c
b/arch/x86/platform/pvh/enlighten.c
index 637bd74ba32d..8040b3fbf545 100644
--- a/arch/x86/platform/pvh/enlighten.c
+++ b/arch/x86/platform/pvh/enlighten.c
@@ -8,11 +8,7 @@
#include
#include
-#include
-#include
-
#include
-#include
#include
/*
@@ -31,21 +27,24 @@ static u64 pvh_get_root_pointer(void)
return pvh_start_info.rsdp_paddr;
}
+/*
+ * Xen guests are able to obtain the memory map from the hypervisor via the
+ * HYPERVISOR_memory_op hypercall.
+ * If we are trying to boot a Xen PVH guest, it is expected that the kernel
+ * will have been configured to provide an override for this routine to do
+ * just that.
+ */
+void __init __weak mem_map_via_hcall(struct boot_params *ptr __maybe_unused)
+{
+ xen_raw_printk("Error: Could not find memory map\n");
+ BUG();
+}
+
static void __init init_pvh_bootparams(void)
{
- struct xen_memory_map memmap;
- int rc;
-
memset(_bootparams, 0, sizeof(pvh_bootparams));
- memmap.nr_entries = ARRAY_SIZE(pvh_bootparams.e820_table);
- set_xen_guest_handle(memmap.buffer, pvh_bootparams.e820_table);
- rc = HYPERVISOR_memory_op(XENMEM_memory_map, );
- if (rc) {
- xen_raw_printk("XENMEM_memory_map failed (%d)\n", rc);
- BUG();
- }
- pvh_bootparams.e820_entries = memmap.nr_entries;
+ mem_map_via_hcall(_bootparams);
if (pvh_bootparams.e820_entries < E820_MAX_ENTRIES_ZEROPAGE - 1) {
pvh_bootparams.e820_table[pvh_bootparams.e820_entries].addr =
diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c
index 41a7d6ad74e0..35b7599d2d0b 100644
--- a/arch/x86/xen/enlighten_pvh.c
+++ b/arch/x86/xen/enlighten_pvh.c
@@ -1,13 +1,18 @@
// SPDX-License-Identifier: GPL-2.0
#include
+#include
+
#include
#include
+#include
#include
#include
#include
+#include
+
/*
* PVH variables.
*
@@ -28,3 +33,18 @@ void __init xen_pvh_init(void)
pfn = __pa(hypercall_page);
wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
}
+
+void __init mem_map_via_hcall(struct boot_params *boot_params_p)
+{
+ struct xen_memory_map memmap;
+ int rc;
+
+ memmap.nr_entries = ARRAY_SIZE(boot_params_p->e820_table);
+ set_xen_guest_handle(memmap.buffer, boot_params_p->e820_table);
+ rc = HYPERVISOR_memory_op(XENMEM_memory_map, );
+ if (rc) {
+ xen_raw_printk("XENMEM_memory_map failed (%d)\n", rc);
+ BUG();
+ }
+ boot_params_p->e820_entries = memmap.nr_entries;
+}
--
2.16.1
[PATCH v9 7/7] KVM: x86: Allow Qemu/KVM to use PVH entry point
For certain applications it is desirable to rapidly boot a KVM virtual
machine. In cases where legacy hardware and software support within the
guest is not needed, Qemu should be able to boot directly into the
uncompressed Linux kernel binary without the need to run firmware.
There already exists an ABI to allow this for Xen PVH guests and the ABI
is supported by Linux and FreeBSD:
https://xenbits.xen.org/docs/unstable/misc/pvh.html
This patch enables Qemu to use that same entry point for booting KVM
guests.
Signed-off-by: Maran Wilson
Suggested-by: Konrad Rzeszutek Wilk
Suggested-by: Boris Ostrovsky
Tested-by: Boris Ostrovsky
Reviewed-by: Juergen Gross
---
arch/x86/Kbuild | 2 +-
arch/x86/platform/pvh/Makefile| 4 ++--
arch/x86/platform/pvh/enlighten.c | 42 +--
3 files changed, 34 insertions(+), 14 deletions(-)
diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild
index 2089e4414300..c625f57472f7 100644
--- a/arch/x86/Kbuild
+++ b/arch/x86/Kbuild
@@ -7,7 +7,7 @@ obj-$(CONFIG_KVM) += kvm/
# Xen paravirtualization support
obj-$(CONFIG_XEN) += xen/
-obj-$(CONFIG_XEN_PVH) += platform/pvh/
+obj-$(CONFIG_PVH) += platform/pvh/
# Hyper-V paravirtualization support
obj-$(subst m,y,$(CONFIG_HYPERV)) += hyperv/
diff --git a/arch/x86/platform/pvh/Makefile b/arch/x86/platform/pvh/Makefile
index 9fd25efcd2a3..5dec5067c9fb 100644
--- a/arch/x86/platform/pvh/Makefile
+++ b/arch/x86/platform/pvh/Makefile
@@ -1,5 +1,5 @@
# SPDX-License-Identifier: GPL-2.0
OBJECT_FILES_NON_STANDARD_head.o := y
-obj-$(CONFIG_XEN_PVH) += enlighten.o
-obj-$(CONFIG_XEN_PVH) += head.o
+obj-$(CONFIG_PVH) += enlighten.o
+obj-$(CONFIG_PVH) += head.o
diff --git a/arch/x86/platform/pvh/enlighten.c
b/arch/x86/platform/pvh/enlighten.c
index 8040b3fbf545..62f5c7045944 100644
--- a/arch/x86/platform/pvh/enlighten.c
+++ b/arch/x86/platform/pvh/enlighten.c
@@ -8,6 +8,8 @@
#include
#include
+#include
+
#include
#include
@@ -40,11 +42,28 @@ void __init __weak mem_map_via_hcall(struct boot_params
*ptr __maybe_unused)
BUG();
}
-static void __init init_pvh_bootparams(void)
+static void __init init_pvh_bootparams(bool xen_guest)
{
memset(_bootparams, 0, sizeof(pvh_bootparams));
- mem_map_via_hcall(_bootparams);
+ if ((pvh_start_info.version > 0) && (pvh_start_info.memmap_entries)) {
+ struct hvm_memmap_table_entry *ep;
+ int i;
+
+ ep = __va(pvh_start_info.memmap_paddr);
+ pvh_bootparams.e820_entries = pvh_start_info.memmap_entries;
+
+ for (i = 0; i < pvh_bootparams.e820_entries ; i++, ep++) {
+ pvh_bootparams.e820_table[i].addr = ep->addr;
+ pvh_bootparams.e820_table[i].size = ep->size;
+ pvh_bootparams.e820_table[i].type = ep->type;
+ }
+ } else if (xen_guest) {
+ mem_map_via_hcall(_bootparams);
+ } else {
+ /* Non-xen guests are not supported by version 0 */
+ BUG();
+ }
if (pvh_bootparams.e820_entries < E820_MAX_ENTRIES_ZEROPAGE - 1) {
pvh_bootparams.e820_table[pvh_bootparams.e820_entries].addr =
@@ -75,7 +94,7 @@ static void __init init_pvh_bootparams(void)
* environment (i.e. hardware_subarch 0).
*/
pvh_bootparams.hdr.version = (2 << 8) | 12;
- pvh_bootparams.hdr.type_of_loader = (9 << 4) | 0; /* Xen loader */
+ pvh_bootparams.hdr.type_of_loader = ((xen_guest ? 0x9 : 0xb) << 4) | 0;
x86_init.acpi.get_root_pointer = pvh_get_root_pointer;
}
@@ -90,13 +109,10 @@ void __init __weak xen_pvh_init(void)
BUG();
}
-/*
- * When we add support for other hypervisors like Qemu/KVM, this routine can
- * selectively invoke the appropriate initialization based on guest type.
- */
-static void hypervisor_specific_init(void)
+static void hypervisor_specific_init(bool xen_guest)
{
- xen_pvh_init();
+ if (xen_guest)
+ xen_pvh_init();
}
/*
@@ -105,13 +121,17 @@ static void hypervisor_specific_init(void)
*/
void __init xen_prepare_pvh(void)
{
+
+ u32 msr = xen_cpuid_base();
+ bool xen_guest = !!msr;
+
if (pvh_start_info.magic != XEN_HVM_START_MAGIC_VALUE) {
xen_raw_printk("Error: Unexpected magic value (0x%08x)\n",
pvh_start_info.magic);
BUG();
}
- hypervisor_specific_init();
+ hypervisor_specific_init(xen_guest);
- init_pvh_bootparams();
+ init_pvh_bootparams(xen_guest);
}
--
2.16.1
Re: [PATCH v9 0/7] KVM: x86: Allow Qemu/KVM to use PVH entry point
On 12/11/2018 5:18 AM, Borislav Petkov wrote: On Mon, Dec 10, 2018 at 11:05:34AM -0800, Maran Wilson wrote: For certain applications it is desirable to rapidly boot a KVM virtual machine. In cases where legacy hardware and software support within the guest is not needed, Qemu should be able to boot directly into the uncompressed Linux kernel binary without the need to run firmware. There already exists an ABI to allow this for Xen PVH guests and the ABI is supported by Linux and FreeBSD: https://xenbits.xen.org/docs/unstable/misc/pvh.html This patch series would enable Qemu to use that same entry point for booting KVM guests. How would I do that, practically? Looking at those here: * Qemu and qboot RFC patches have been posted to show one example of how this functionality can be used. Some preliminary numbers are available in those cover letters showing the KVM guest boot time improvement. Qemu: http://lists.nongnu.org/archive/html/qemu-devel/2018-12/msg00957.html qboot: http://lists.nongnu.org/archive/html/qemu-devel/2018-12/msg00953.html I might still need to do some dancing to get stuff going. Is your question about what options you need to provide to Qemu? Or is your question about the SW implementation choices? Assuming the former... once you have compiled all 3 new binaries (kernel, Qemu, and qboot) then you simply invoke qemu the same way you normally invoke qemu with qboot + kernel binary, except you provide the vmlinux (uncompressed) kernel binary when specifying the "-kernel" parameter. Qemu/qboot will automatically detect that you have provided an ELF binary, find the PVH ELF note to locate the entry point, and proceed to boot the kernel via that method. On the other hand, if you leave all the Qemu options as-is, but simply provide the bzImage (compressed) kernel binary from the same build, Qemu/qboot will boot the way it has always done and not look for PVH. To make it more concrete, here's an example of how I had been invoking PVH boot recently: x86_64-softmmu/qemu-system-x86_64 \ -name testvm01 \ -machine q35,accel=kvm,nvdimm \ -cpu host \ -m 1024,maxmem=20G,slots=2 \ -smp 1 \ -nodefaults \ -kernel binaries/vmlinux \ -object memory-backend-file,id=mem0,share,mem-path=binaries/containers.img,size=235929600 \ -device nvdimm,memdev=mem0,id=nv0 \ -append 'console=ttyS0,115200,8n1 root=/dev/pmem0p1 panic=1 rw init=/usr/lib/systemd/systemd rootfstype=ext4' \ -bios binaries/bios.bin \ -serial mon:stdio Thanks, -Maran Thx.
Re: [PATCH v8 1/7] xen/pvh: Split CONFIG_XEN_PVH into CONFIG_PVH and CONFIG_XEN_PVH
On 12/7/2018 7:14 AM, Paolo Bonzini wrote: On 07/12/18 14:58, Juergen Gross wrote: On 07/12/2018 14:52, Paolo Bonzini wrote: On 07/12/18 14:50, Juergen Gross wrote: The PVH boot entry is in the same bzImage binary as the normal one. Its just another entry, similar to the Xen PV boot entry. So the binary arch/x86/boot/bzimage can be booted either on bare metal via grub2 or other boot-loaders, as Xen PV-guest, as Xen PVH-guest, or as KVM PVH-guest. So one build and one binary. The non-standard boot entries (PV- or PVH-node) are found via ELF-notes by the boot loader (qemu in case of KVM). But the bzImage is not an ELF binary, and it is compressed, isn't it? /me is confused. :) grub2 (and qemu, too) can decompress it. And the decompressed result "vmlinux" is an ELF-binary. Aha - for KVM, the main advantage of PVH would be to skip the cost of decompression, and that is what confused me (also we probably prefer not having any decompression code running in QEMU, since that increases the attack surface; there's no real disadvantage to using the existing linuxboot code if we're given a bzImage). So, at least for now, KVM would go with the two-binaries/one-config approach. Yeah, the way we have been testing with the Qemu/qboot changes that Liam has out for review, if you provide the bzImage binary in the -kernel argument, legacy behavior is followed. However if you provide the vmlinux binary (from the same kernel build), Qemu recognizes it as an ELF binary, looks for the presence of the PVH ELFNOTE, and (if the ELFNOTE in question is found) uses that entry point instead. So at this point, the only feedback/comment still outstanding from you is the one about removing KVM_GUEST_PVH right? I'll hold off on sending a v9 until next week to see if there is any additional feedback or test results. Thanks, -Maran Sorry for having you lecture me, it's much clearer now. Thanks, Paolo
