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Subject[tip: x86/vmware] x86/vmware: Update platform detection code for VMCALL/VMMCALL hypercalls
The following commit has been merged into the x86/vmware branch of tip:

Commit-ID: bac7b4e843232a3a49a042410cf743341eb0887e
Gitweb: https://git.kernel.org/tip/bac7b4e843232a3a49a042410cf743341eb0887e
Author: Thomas Hellstrom <thellstrom@vmware.com>
AuthorDate: Wed, 28 Aug 2019 10:03:50 +02:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Wed, 28 Aug 2019 10:48:30 +02:00

x86/vmware: Update platform detection code for VMCALL/VMMCALL hypercalls

Vmware has historically used an INL instruction for this, but recent
hardware versions support using VMCALL/VMMCALL instead, so use this
method if supported at platform detection time. Explicitly code separate
macro versions since the alternatives self-patching has not been
performed at platform detection time.

Also put tighter constraints on the assembly input parameters.

Co-developed-by: Doug Covelli <dcovelli@vmware.com>
Signed-off-by: Doug Covelli <dcovelli@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Doug Covelli <dcovelli@vmware.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-graphics-maintainer@vmware.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: virtualization@lists.linux-foundation.org
Cc: <pv-drivers@vmware.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190828080353.12658-2-thomas_os@shipmail.org
---
arch/x86/kernel/cpu/vmware.c | 88 ++++++++++++++++++++++++++++-------
1 file changed, 71 insertions(+), 17 deletions(-)

diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 3c64847..757dded 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -34,30 +34,65 @@
#undef pr_fmt
#define pr_fmt(fmt) "vmware: " fmt

-#define CPUID_VMWARE_INFO_LEAF 0x40000000
+#define CPUID_VMWARE_INFO_LEAF 0x40000000
+#define CPUID_VMWARE_FEATURES_LEAF 0x40000010
+#define CPUID_VMWARE_FEATURES_ECX_VMMCALL BIT(0)
+#define CPUID_VMWARE_FEATURES_ECX_VMCALL BIT(1)
+
#define VMWARE_HYPERVISOR_MAGIC 0x564D5868
#define VMWARE_HYPERVISOR_PORT 0x5658

-#define VMWARE_PORT_CMD_GETVERSION 10
-#define VMWARE_PORT_CMD_GETHZ 45
-#define VMWARE_PORT_CMD_GETVCPU_INFO 68
-#define VMWARE_PORT_CMD_LEGACY_X2APIC 3
-#define VMWARE_PORT_CMD_VCPU_RESERVED 31
+#define VMWARE_CMD_GETVERSION 10
+#define VMWARE_CMD_GETHZ 45
+#define VMWARE_CMD_GETVCPU_INFO 68
+#define VMWARE_CMD_LEGACY_X2APIC 3
+#define VMWARE_CMD_VCPU_RESERVED 31

#define VMWARE_PORT(cmd, eax, ebx, ecx, edx) \
__asm__("inl (%%dx)" : \
- "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \
- "0"(VMWARE_HYPERVISOR_MAGIC), \
- "1"(VMWARE_PORT_CMD_##cmd), \
- "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) : \
- "memory");
+ "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \
+ "a"(VMWARE_HYPERVISOR_MAGIC), \
+ "c"(VMWARE_CMD_##cmd), \
+ "d"(VMWARE_HYPERVISOR_PORT), "b"(UINT_MAX) : \
+ "memory")
+
+#define VMWARE_VMCALL(cmd, eax, ebx, ecx, edx) \
+ __asm__("vmcall" : \
+ "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \
+ "a"(VMWARE_HYPERVISOR_MAGIC), \
+ "c"(VMWARE_CMD_##cmd), \
+ "d"(0), "b"(UINT_MAX) : \
+ "memory")
+
+#define VMWARE_VMMCALL(cmd, eax, ebx, ecx, edx) \
+ __asm__("vmmcall" : \
+ "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \
+ "a"(VMWARE_HYPERVISOR_MAGIC), \
+ "c"(VMWARE_CMD_##cmd), \
+ "d"(0), "b"(UINT_MAX) : \
+ "memory")
+
+#define VMWARE_CMD(cmd, eax, ebx, ecx, edx) do { \
+ switch (vmware_hypercall_mode) { \
+ case CPUID_VMWARE_FEATURES_ECX_VMCALL: \
+ VMWARE_VMCALL(cmd, eax, ebx, ecx, edx); \
+ break; \
+ case CPUID_VMWARE_FEATURES_ECX_VMMCALL: \
+ VMWARE_VMMCALL(cmd, eax, ebx, ecx, edx); \
+ break; \
+ default: \
+ VMWARE_PORT(cmd, eax, ebx, ecx, edx); \
+ break; \
+ } \
+ } while (0)

static unsigned long vmware_tsc_khz __ro_after_init;
+static u8 vmware_hypercall_mode __ro_after_init;

static inline int __vmware_platform(void)
{
uint32_t eax, ebx, ecx, edx;
- VMWARE_PORT(GETVERSION, eax, ebx, ecx, edx);
+ VMWARE_CMD(GETVERSION, eax, ebx, ecx, edx);
return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC;
}

@@ -136,7 +171,7 @@ static void __init vmware_platform_setup(void)
uint32_t eax, ebx, ecx, edx;
uint64_t lpj, tsc_khz;

- VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
+ VMWARE_CMD(GETHZ, eax, ebx, ecx, edx);

if (ebx != UINT_MAX) {
lpj = tsc_khz = eax | (((uint64_t)ebx) << 32);
@@ -174,10 +209,21 @@ static void __init vmware_platform_setup(void)
vmware_set_capabilities();
}

+static u8 vmware_select_hypercall(void)
+{
+ int eax, ebx, ecx, edx;
+
+ cpuid(CPUID_VMWARE_FEATURES_LEAF, &eax, &ebx, &ecx, &edx);
+ return (ecx & (CPUID_VMWARE_FEATURES_ECX_VMMCALL |
+ CPUID_VMWARE_FEATURES_ECX_VMCALL));
+}
+
/*
* While checking the dmi string information, just checking the product
* serial key should be enough, as this will always have a VMware
* specific string when running under VMware hypervisor.
+ * If !boot_cpu_has(X86_FEATURE_HYPERVISOR), vmware_hypercall_mode
+ * intentionally defaults to 0.
*/
static uint32_t __init vmware_platform(void)
{
@@ -187,8 +233,16 @@ static uint32_t __init vmware_platform(void)

cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0],
&hyper_vendor_id[1], &hyper_vendor_id[2]);
- if (!memcmp(hyper_vendor_id, "VMwareVMware", 12))
+ if (!memcmp(hyper_vendor_id, "VMwareVMware", 12)) {
+ if (eax >= CPUID_VMWARE_FEATURES_LEAF)
+ vmware_hypercall_mode =
+ vmware_select_hypercall();
+
+ pr_info("hypercall mode: 0x%02x\n",
+ (unsigned int) vmware_hypercall_mode);
+
return CPUID_VMWARE_INFO_LEAF;
+ }
} else if (dmi_available && dmi_name_in_serial("VMware") &&
__vmware_platform())
return 1;
@@ -200,9 +254,9 @@ static uint32_t __init vmware_platform(void)
static bool __init vmware_legacy_x2apic_available(void)
{
uint32_t eax, ebx, ecx, edx;
- VMWARE_PORT(GETVCPU_INFO, eax, ebx, ecx, edx);
- return (eax & (1 << VMWARE_PORT_CMD_VCPU_RESERVED)) == 0 &&
- (eax & (1 << VMWARE_PORT_CMD_LEGACY_X2APIC)) != 0;
+ VMWARE_CMD(GETVCPU_INFO, eax, ebx, ecx, edx);
+ return (eax & (1 << VMWARE_CMD_VCPU_RESERVED)) == 0 &&
+ (eax & (1 << VMWARE_CMD_LEGACY_X2APIC)) != 0;
}

const __initconst struct hypervisor_x86 x86_hyper_vmware = {
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